My 23 year old gelding (retired now) has off/on symptoms that are confusing as I have not ever seen or heard of before.  He sometimes shows symptoms of colic but is not colic.  He will get up from laying down and has what I call muscle spasms through his flank region that goes along to his shoulder.  Most of the time it is either on one side or the other.  Flank region being real tight, has very good gut sounds, poops but will walk or trot around, paws and then shows signs of cramping in his flank region and will twitch like he is being biten by a thousand flies.  No flies as it is winter.  I give him Kolik Eaz from Silver Lining and walk him and he calms down and I put on a magnetc blanket and then he relaxes and acts like nothing happened.  When these episodes occur he is very agitated like it scares him which scares me also.  Has anyone ever seen or had a horse do this?  I am going to talk to my Vet but just curious if anyone on here has ever seen or heard of this.

Mine do that when they have "gas colic." I usually just do banamine like regular colic and they settle down fine after a bit. That might be what yours is doing. I've had one do it for a few days straight when the weather/temp was changing 

Had a mare do this. After taking her to the vet several times and after the last time, he decided it must be a hindgut ulcer, so he told me to treat it. I did and she was fine. 

It definitely sounds like gas colic.  We had a horse that would do this.  We feed him Platinum Performance supplement and it has solved the problem.

He already is on the Forco.  

There was a thread on here about someone that had a horse doing something similar.   Like the horse's skin would shake and move.  Or maybe muscles under it?   They had a video I believe.   Was it associated with tying up???

No I don't think it is associated with tying up.  I thought that at first also.

Kind of also sounds similar to HYPP? If it's not colic? Hopefully he gets better soon!! :)

He does not have that gene in his bloodline as far as I have researched and I owned both of his mother and father and I had a full sister to him and I also have a full brother to him.  So IDK don't think it is that.

I wish I could remember that thread.   The horse almost seemed to spasm under the skin in the video if I remember right.  Maybe it wasn't a tying up thread. . . 

PSSM2 will present that way in many horses.  Looks like colic but not - good gut signs, but they are very uncomfortable.  Muscles will spasm and hurt big time. 

If I read right the PSSM2 is associated to tying up.  Is this correct?  If so then no I don't think it is PSSM2 as he is not reluctant to walk in fact he would rather trot around in circles.  

Is your horse housed on sand? I have experienced mild sand colics that present in a similar fashion.

No not on sand on pasture with grass (very limited grass) at this time of year.

My vet said that he thinks a lot of older horses that have colic signs but never actually colic may have stones, either intestinal or kidney type. He actually thinks that stones maybe underdiagnosed because often when we lose one, we assume colic and never research it further.