I am an X exctasy user and have similar problems. I don't have pains or tightness in my head, but when I start to fall asleep my mind almost seems to realize that i am about to have a dream and my mind actually wakes me up... This sometimes happens if I am having a bad dream, while in dream it's like I become aware that I can stop things by just opening my eyes. So in dream i seam to think real hard about its only a dream its only a dream and I wake up. Ambien helped as far as that goes, but for the weird sensations you get, I don't know, I would definitly ask a Dr. GOOOD LUCK!
EDIT:My only experience with 5-HTP was when I would take it before I rolled. (took x, not sure of all your guys's is lingo) Seemed to make me roll harder, could have been all mental who knows, but I don't think it would hurt to try. Its OTC so it can't be real dangerous, REMEMBER THOUGH, I AM LIKE YOU, WITHOUT A MEDICAL DEGREE, SOOO PLEASE DON'T BLAME ME IF YOU NEVER SLEEP AGAIN AFTER TRYING IT!!!