Mom, 40, Who Never Smoked Thought 'Mild Cough' Was Allergies — but It Was Lung Cancer (Exclusive)

Stephanie Williams has been documenting her health journey since having part of her lung removed

• Stephanie Williams, 40, developed a slight cough and thought it was allergies or undiagnosed COVID

• Williams, who never smoked, asked her doctor for an X-ray — which is when a mass in her lung was discovered

• She underwent chemotherapy and the removal of part of her lung, sharing her recovery journey on TikTok

Stephanie Williams said it all started with a "persistent, mild cough."

Her daughter, Liza, had just started kindergarten in 2021, and Williams, now 40, tells PEOPLE, “I noticed when I picked her up, I would start talking to her and asking how her day was and I would have to cough mid-sentence. It would just kind of catch my breath for a moment.”

She said she had her annual physical coming up and mentioned the cough to her doctor.

“We had a discussion on whether this could be seasonal allergies,” she said, “Or we could try reflux medication.”

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Since it was “still sort of in the throes of the pandemic,” the Harrisburg, Penn., resident said she asked for a chest X-ray, telling PEOPLE, “I thought maybe I had had COVID and never known it. “

Her doctor had an X-ray machine right in the office. “As soon as she looks at it," Williams tells PEOPLE, her doctor said, " 'Oh my God.' "

She tells PEOPLE that she saw her X-ray on the screen, and “I saw like a big cloudy oval on the right side of my chest over my lung. I remember thinking, 'What is that?' "

A former home health care nurse, Williams said, "I know enough about anatomy to know that there's no structure in the body that looks like that right there.”

Her doctor told her she urgently needed a CT scan — which showed a mass that was "highly suspicious for neoplasm. I'm like, 'I feel like that's code for this is probably cancer.' ”

Related: Big Bang Theory Star Kate Micucci Reveals Lung Cancer Diagnosis: 'Never Smoked a Cigarette in My Life'

In fact, it was, lung cancer — and Williams would need surgery to remove it.

“I was what they call a 'never-smoker," she tells PEOPLE, "There were no environmental risk factors that we identified. I didn't have a family history of lung cancer."

"It was really a shock because there was no, like, 'Oh yeah, you did work in that uranium mine.' There was no ground for this. There was no explanation at that time."

As she prepared for surgery — and recovery — Williams recalled how hard it was to “still be a mom to a young child.”

“Those little details, like the mother's touch, I was worried about,” Williams says. “Liza has this beautiful curly hair and we use a lot of hair clips to keep it out of her face, especially when she's at school. And before my surgery, I sent a bunch of hair clips and a little bag to her teacher, with the saddest note."

She continued, "It was just like, 'Hey, I'm gonna be down for the count for a little bit and we're gonna have multiple caregivers helping out with Liza…so if her hair is in her face, can you please put it back for her?' ”

"It almost makes me cry to think about," she shared with PEOPLE.

Williams said she had two lobes of her right lung removed, and started chemotherapy. She was also tested positive for the ALK+ genetic mutation.

ALK+ — or Anaplastic Lymphoma Kinase Positive — is a “genetic alteration of your lung cells’ DNA that causes these cells to grow abnormally and ultimately behave as cancer cells,” the Lung Cancer Foundation of America explains.

“Younger patients who have never smoked — usually 55 and under — are most likely to be diagnosed as being ALK+."

Related: Kathy Griffin Got Lung Cancer Despite Never Smoking — Here's What to Know About the Condition

In other lung cancer patients who never smoked, the U.S. Centers for Disease Control says "Researchers estimate that secondhand smoke contributes to about 7,300 and radon to about 2,900 of these lung cancers."

Williams started documenting her cancer journey on TikTok — and her account quickly grew to nearly 20,000 followers.

She says the videos that usually end up going viral are the ones “that are pretty basic about like, 'Hey, this is the difference between stage one, two, three, and four of cancer' or 'Hey, here's three things to remember if you've just been diagnosed with lung cancer.' ”

“I think goes to show that at the beginning when someone's diagnosed, it's so overwhelming that really simple information goes a long way," she said of her videos' popularity.

While she generally keeps things positive on her TikTok — and is “doing really well right now” — Williams says “this isn't guaranteed not to come back. I don't feel comfortable saying I'm cured or I'm in remission or even that I'm cancer-free. because I don't have a microscope to look everywhere in my body.”

She fundraises on behalf of the Lung Cancer Foundation of America, telling PEOPLE, “That's always on my mind. I can't have a headache, my back can't hurt without me worrying. 'Is this a brain met? Is this bone metastasis?' ”

These days, she says, “I've calmed down a little the farther away I get from diagnosis — that every ache and pain or every cough doesn't alarm me as much as it used to. [But] I'd be lying if I said it didn't worry me a little each time.”

“The last time I thought it was nothing, it changed my life and my family's life,” she says. "So I don't really have the luxury of being like, 'It's probably nothing,' because I did that once and I was dead wrong.”

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