Hello. I'm Dr. Christensen.
I'm sorry you're uncomfortable.
Osteoarthritis frequently involves the hips, and
hip arthritis often causes groin pain, particularly when you bear weight or rotate your leg inward and outward. However, if your x-ray didn't reveal significant hip arthritis, there's probably something else going on here.
It's possible your new exercise has strained one of your hip adductors (i.e., a "groin pull"). If that's the case, your pain should increase -- just like it would with arthritis -- with hip movement, especially with hip flexion (drawing your knee toward your chest), rotating your leg inward, or adduction (drawing your legs together).
Hernias tend to cause more pain with coughing,
sneezing or bearing down (as if you're trying to have a bowel movement). Unfortunately, some hernias can be difficult to identify: femoral hernias, which are more common in women, can elude diagnosis because they protrude into the femoral canal, which is a space deep within your groin.
All things considered, it's more likely your discomfort is due to a
muscle strain or some other musculoskeletal problem. However, I'd suggest you pass this by your doctor to make sure nothing else is afoot. Hernias can incarcerate or strangulate and cause serious complications.
I hope that answers your question. Good luck!