Not only had the same thing, it got worse...
Eventually, I started having these seizing spasms of entire back: can't ignore that, it will make you drop to the floor in a sec.
After a year+ of cleansing(LF, para, bowel), it's much better...
When I start having the freezing-up sensation in my neck, between the shoulders & back, I take it as a sign to start preparing for another flush(have done 18 so far, still getting results).
Also, as you cleanse, and your liver, lymph, bowels get cleared of toxins, you may experience spontanious cracking of the back and cranium (this is agood thing: very relieving). Kind of reverse of spasms.
ALSO: make sure you get enough calcium and magnesium, EFAs, v.important.
Do stretching, deep breathing,get some sun, get a massage,