Suggest Treatment For Severe Pain In Leg After Semitendinosus Injury

I think I have Semitendinosus injury. First thing in the day is seems fine. The more I walk it seems to get tighter. It sends like shooting pains with use and the transition from sitting to standing or the other way really hurts. If I have been resting for a while then I can walk a while before it comes back. I think I hurt myself while doing seated reverse curls, single leg.