In my opinion you have glutus medius tightness not spasm , because there is muscle imbalance . you have weak abdominal musles and tight back muscles which move the pelvic anteriorly and that affect your walk (pain) .there is dysfunction Iadvice you to go to physiotherapist and treatment must be SWD and streching exercises for back muscles and strengthening for abdominal muscles. No benefit from the hot pads because the muscles deep and SWD can reach the muscles and heat it so pain reduced and exercise verey effective after SWD.