Chica has a muscle spasm in her back. I see it twitching when she is lying down to rest or sleep. It has been going on for about a month. I took her to the vet today. He doesn't know what could be causing this problem. He prescribed an anti-inflamatory to see if it helps. IF it doesn't help the vet will take x-rays and check blood samples. Has anyone had this problem with a pet. ?????