Muscle spasms while trying to sleep?

Last night I was exhausted and about to fall asleep but whenever I would close my eyes I would be on the verge of sleep and my muscles would tense a lot then spasm and it went on for hours. I've had some bad past memories from things happening while I was asleep but I'm working on getting over these and it doesn't bother me anymore. Could I subconsciously be remembering the past or why would I have these harsh muscle spasms?