I was in goals and saved a goal by kind of sitting down and thrusting the leg out like an ice hockey goalie. This overstretched the glute and hasn’t been the same since. How to stretch/rehab ?

I've come back to football about 6 weeks ago, after a two-year break, and after every training session and game I've played, I'm experiencing pain in my right hip flexor region, most notably when I move my leg upwards and when I kick a football. The pain resolves itself after a few days but then reoccurs once again when I go back to exercise. Could this be due to weak hipflexor muscles and/or muscle strain? Any advice on what I should do?