Please ask a PT or OMT to check your psoas and iliacus. What you describe is pretty classic for iliopsoas spasm/tightness/structural shortening secondary to sciatica or back injury. This can start unilateral, and later become bilateral. Ask them if myofascial release (through the abdomen, a kind of deep massage) or strain-counterstrain would help. If they would help, the PT or OMT (or DO if you have access to one) will be able to teach you how to do both techniques on yourself.