Thank you. Doing a GI follow up with an endoscope to rule out esophegeal issues. Todd
I'd pay attention to changes in your workout abilities but certainly continue to work out. If you find yourself breathless and/or have chest heaviness or pressure, I'd stop immediately and contact your doctor. Generally, sharp, stabbing pains aren't cardiac issues.
An Angiogram is the gold test to determine if someone has a blockage. The fact that you had a nuclear stress test that was normal is very encouraging, perhaps you are experiencing some joint/muscle discomfort.
My son is your age and was your height and weight, a runner and gym rat and had similar pain issues. He lost about 30 pounds and the pains disappeared. It might help you to drop some weight and see if the pains disappear.
That said, never ignore chest discomfort, especially a feeling of pressure, or squeezing, and breathlessness was ALWAYS a symptom to me of oncoming heart issues.