I feel the same thing, sometimes it is like a fluttering or muscle spasm but I know it's the worms. Sometimes I even feel it in my back. When I took the medicine was when they started biting me from the inside. I took the medicine to keep them from reproducing but continued hitting them with herbs and other anti-parasitic foods and they just keep passing in my stool. This double punch is really helpful in freeing your body from this stuff.