I would like to suggest that if there is a sudden onset in this, review your medications and their side effects. My Mom & I had a cramping problem when walking several years ago from an asthma medication which has since been taken off the market. My husband had it from a blood pressure med, and my friend from a statin. My sister had nighttime leg cramping problem from a supplement that reacted with one of her prescriptions.

After reading "the fine print" we determined in each case that it was either an unusual side effect, or an interaction with another med we were taking. It is not a bad idea any time you have a new issue or a new med to review both the side effects of all meds and supplements, and possible adverse reactions/interactions from taking them together. Two years ago my primary doc couldn't figure out how to stop a constant asthma attack I was having - she consulted the Pharm Doc in our clinic who reviewed my meds and said "one of her Rx, a beta-blocker, is counteracting her asthma meds which are beta-agonists. Put her something else!"

It is definitely worth checking thoroughly.
Sue