This is to describe Alpha's limp in his leg.

Breif summary of how alpha got his limp!
Alpha was on a job to arrest a man, peacefully. He and his team got caught with the man being violent. They tried their best to calm the man and take him in peacefully, but, it did not work. As the man was firing his weapon he aimed his weapon at Staptan, a young man who is Alpha's work partner, In fear that Staptan might get seriously hurt Alpha took the chance to save him and got hit in the thigh close to the knee. The weapon of choice was a shot gun, which caused several bullet pebbles to shatter within his leg.

What could have caused the limp:
Due to being shot in the thigh near the knee there could possibly be a few things that caused it. Torn ligaments, broken the bone in either thigh or knee, nerve damage, or torn muscles.
Now if the muscle is/was damaged, it would probably cause scar tissue on the muscle and would not allow the muscle to stretch correctly.

The types of pain he may experience:
Alpha could experience lower back, hip, knee and overall leg pains. Due to the limp he'd have to walk in an abnormal form causing strain on the hip and lower back. Knee also due to limp or if there was damage done to his knee. Might also experience painful random cramps now and then if the muscle is damaged. Cold weather might also cause some pain in his leg as well.

(also just sayin, Im no expert. Hell looking at causes made my knee feel weak, so if I am wrong or you guys have ideas. Share with me!