Pain over the side of the hip is commonly related to changes in the health of the tendons that join the gluteal (buttock) muscles to the hip, and sometimes of the nearby bursae (fluid filled sacks that help reduce friction between tendons and bones). The condition may be diagnosed as gluteal tendinopathy or tendinitis, trochanteric bursitis or Greater Trochanteric Pain Syndrome (GTPS) which encompasses both. The good news is, that regardless of the diagnostic term and whether in your case the tendons or bursae seem to be most affected, the underlying cause appears to be the same and strategies to improve health of one, will help the other as well.