Hello, I'm new to this.
I often go three or four days feeling ok and then something seemingly small will trigger me and my whole body - especially back, neck and shoulders - will suddenly lock. It is painful but what I find most difficult about it, is that it alters my mood too, I emotionally can not relax because my body is in this spasm, and the spasm can last for a number of days. The only thing that I have found that unravels it is a proper sauna treatment - including, a freezing cold shower or plunge pool at intervals (so sauna, then cold shower, then steam room, then ice plunge pool, then sauna again, and another cold plunge pool). THe heat really helps but somehow the cold really gets into the muscles and really helps to release them. Also Bikram yoga helps. I find the whole muscle lock thing difficult because it is unpredictable, and I can be feeling fine and then suddenly my whole day is ruined, I lose all my confidence - I seem to turn (inwardly) into a child.