What are common causes of left thigh muscle/joint tightness?

Any injury to the -: Thigh or joint area, can cause bleeding around and in the muscles, resulting in loss of motion of the nearby joint, initially due to the pain, then scar tissue formation, or even myositis ossificans, if treatment is not started early enough, with range of motion exercises, ultrasound, pain meds, ice/heat, pain meds. With early treatments the risk of m. Ossificans has greatly reduced nowadays.