All I can find online refers to "muscle cramps" which this isn't, at least not in the sudden extreme charley horse sense. Internet searches give info that "muscle cramps" can be caused by hypo or hyper thyroid, and low potassium.
Aspirin, relieves the immediate knee pain the muscle contraction is causing, but it also seems to make it worse as the days go by. (have experimented and this seems comfirmed)
I guess I'm looking for nutritional/hormonal deficiencies or excesses, as this is something I haven't suffered for at least a year, but here it is back again these past few weeks.
thanks for any ideas,