you seem to have a mechanical back pain.  do you face the pain around the dimple area above the buttock crease.  A cronic long standing pain usually weakens the muscles around the area leading to repetitive injuries.  massage should be avoided.  This can cause your symptoms and inflammation around the area to flare up.  Have it checked up before it leads to pain on both sides.  A asymmetrical pressure around the pelvis can increase pain. 

Hello, It's an SI joint dysfunction. don't get pressure massages on that area. there might be a Sciatic nerve compression in the buttock. consult a physiotherapist and get therapy done. You may need an MRI scan to reveal if any slip discs are present. avoid all athletic activities for 2 weeks.