Muscle spasms seems like it fits the best, the weird thing is that it happens so frequently with me, about 40% of the days in a year and
those days are usually grouped together
. 90% of the time it happens it's while I'm laying down (and thus, trying to go to sleep) and when it does happen I can stand or sit straight up to make the thumping go away, but once I lay down again it comes back.
This has been going on for probably more than 7 years.
Is this cause by muscle spasms? Is this curable?