I may be off the mark but what is called a cns button may be stuck. I recall having a similar problem with an athlete and Michael Khmel knew a specialist who fixed the problem.
The body is programmed with a defence mechanism, a baby will always fall on it’s butt. When you train you reprogram the cns. On occasions an incident can happen (usually a fall) where a mixed signal of old and new get turned on together. can be fixed with acapuncture or applying pressure to the right position, hurts like hell.