Hello there,,,,well a pretty challenging case...most of the people you consulted thought that maybe its a muscle pull or some sort of nerve impingement....i have had a similar case presented before me 2 years back .... initially with physio electrical modalities n stretching the patient did hav some relief but was again back to his symptoms ..... later on with sonography & reassessment we found out that the person had mild appendicitis and inguinal hernia.
Xray's would usually miss certain minute soft tissue anamolies
Next Steps
You need a through Physical Assessment,along with radiological and pathological tests.
do resort back if you have any queries
Regards & take care.