You might question the original diagnosis and explore options related to piriformis syndrome. Make sure it releases and is well lengthened with stretching. This is a very common problem with cycling and I’ve seen it overlooked by pretty decent PTs when there was no initial obvious mid to upper buttock pain. Upon closer inspection you may find ropey muscle groups within the deeper buttock that are potentially tender to pressure but don’t necessarily have to be. Had any additional posterior thigh pain or mysterious knee pain lately on that same side?