What would be possible causes for hip pain that is episodic in a 27yr old for 2 years no injury but did martial arts for 15 yrs I can barely walk!?

Overuse. Hip pain could be a sign of arthritic condition. If you did martial arts. That is a lot of stress on the hip. Since walking is difficult, I am concerned about an arthritis or a bursitis. You may want to start with having an examination with a sports medicine physician and then have an x-ray.
Hip pain. Many options here including early arthritic condition. Also labral injury and femoral acetabular impingement, sports hernia, etc. Would have it checked out by a sports medicine physician.