** Thanks for contacting with your health concern. 1. As I m unable to examine you directly, thus according to your symptoms, I m of the following opinion: i. It could be a twisting injury which might have cause inflammation or damage to muscle, bones, and joints of the leg Or combination of all three. ii. it could be a sprain/strain [stretching of ligament/muscle/tendon] which can cause swelling and inflammation resulting in pain. iii. Pain in one leg would tend to be due to local problem and not necessarily due to systemic involvement, as such initially consult with your primary care provider, since it could be simple sciatica problem [inflammation of sciatic nerve] who might refer you to an orthopedic surgeon for necessary examination [blood test and imaging of back] and to exclude any other medical condition like a blood clot. PS. although most cases of groin pain do not require medical attention, but if the symptoms are severe, you should see a doctor as these symptoms may indicate a more serious condition. iv. If with home care treatment like rest, taking a break from physical activity, applying Ice or taking over the counter medicine like tylenol does not work your doctor might prescribe drugs that reduce inflammation to help relieve your symptoms.