work on getting internal rotation back whatever that takes. mobilisation, soft tissue release etc. then look at hip position. poor activity/overactivity in glutes/tfl. if there is decreased rom into internal rotation in a neutral hip position and in 90 of hip flexion i wouldnt personally be focusing my attention on piriformis, but we dont have that info so...

a photo of posture etc would be nice. exact area of symptoms would also be nice. but then it would be nice to be able to do a biomechanical assessment and a spinal exam too!