Hip Flexor Strain is caused by stretching or tearing one of the hip flexor muscles and/or tendons, past its capacity.  The hip flexor muscles are a group of multiple muscles that help raise your upper leg up(flex the hip).  This can occur from many different things but most seen from sports injuries, running, weightlifting, laboring jobs, and desk jobs.

Symptoms of a Hip Flexor Strain are, dull ache, sharp/stabbing pin, and sometimes pinching in the hip.  It can cause limitations in movement as well as pain with movement, weakness in the hip/muscles in the hip region, and trouble sitting, standing, and walking.  If left untreated it can lead to increased severity of pain and limitations as well as possibilities of further injuries.

The best course of action is to seek professional care that can properly evaluate and diagnose the issue.  This will help them build a proper treatment plan that can help decrease pain, improve mobility and stability as well as educate how to manage the issue and prevent it from reoccurring.