25-year-old diagnosed with cancer shares his journey on social media to help others

What began as symptoms of fatigue for one Florida man became a life-changing cancer diagnosis at age 25.

Jace, who asked that his last name not be used to protect his privacy, told "Good Morning America" he attributed the fatigue he experienced in early 2023 to being a workaholic.

The 25-year-old is the co-founder of a marketing company and an entrepreneur in the health and wellness industry.

"I'm very passionate about what I do, and I love what I do," he told "GMA." "And for that reason, you know, I tend to push the limits of my energy a little bit."

Prior to his cancer diagnosis, Jace said he had no serious health issues and led an active lifestyle, often going for a run or golfing as part of his regular activities.

"I've been a very healthy person my whole life," he said, adding that he came from a very fitness-oriented family.

The Florida resident said whenever he found himself in New York City on business trips, he enjoyed running through Central Park.

However, during a run at the park last September, he said he felt his "energy was low."

"I could not catch my breath. It was alarming," he said. "I had to stop multiple times to catch my breath. My heart was pounding incredibly hard. It felt like it was beating out of my chest."

Not long after the incident, Jace said he began experiencing severe back pain.

"[It was] in my upper back toward my shoulder blades, and it was horrible," he said. "I had shooting pains all the way through my arm."

Advocating for himself to find a diagnosis

To check on the pain, Jace said he went to urgent care, where he was treated with muscle relaxer and steroids.

A second doctor visit led to Jace being put on medication for what his doctor thought was just acid reflux. At another doctor visit, Jace said he was told to see a sports injury specialist for his pain.

Jace said he began to feel despair, telling "GMA," "I just felt like nothing was working."

Following additional testing, Jace said doctors discovered three masses in his chest that were equivalent to the size of a softball.

After losing 20 pounds and experiencing more symptoms like night sweats, Jace saw an oncologist, whom he said diagnosed him with non-Hodgkin lymphoma, a type of cancer in which "malignant cells form in the lymph system," according to the National Cancer Institute.

Battling cancer in the public eye

After the shock of his diagnosis, Jace said he decided to document his cancer journey on social media to help raise awareness.

His Instagram account, JaceBeatsCancer, has amassed more than 435,000 followers.

"I decided to start posting content not just to document the journey for myself but to document, really, the journey for my loved ones and my friends so that they could see how I was doing and what I was going through," he explained. "I had no idea that people would be drawn to this content."

Jace shares everything on his social media accounts from his emergency room visits to undergoing chemotherapy and antibody therapy -- and experiencing the side effects that come with those therapies -- to connecting with other people who are battling cancer, or who have loved ones doing so as well.

He has also shared moments of vulnerability through his cancer journey, including writing his own will with his father at the age of 25.

"The most compelling lesson that I've learned through this is to understand what's truly important in life, and for me, what's truly important is helping other people and spending time with those you love," he said. "If you can do those two things, you will have a very, very fulfilled life."

To keep himself motivated, Jace said he focuses on the new perspective he has gained and reminds himself to not give up.

Jace's oncologist, Dr. Steven B. Newman of the Florida Cancer Specialists & Research Institute, told "GMA" that he is currently going through "a very tough regimen" of both chemotherapy and a monoclonal antibody therapy.

He added that Jace's chances of beating the cancer are "extremely good." He said Jace's desire and determination to get better has inspired himself to continue the work he does in his profession.

"This is my 42nd year in medical practice as an oncologist. I've been doing this for a long time, and it is patients exactly like Jace that keep me coming to work every day," Newman said. "It's incredibly invigorating. It's challenging, but working with someone like him, who has exceptional energy, intelligence and insight, makes it even more special."