I experienced 5 IPIR's that sound similar to yours in the 4 1/2 months I was on it, and then both I and my neuro threw in the towel. I also experienced the cold chills and shaking after all the other heart/shortness of breath/flushing ... symptoms were over and they lasted for about 2 hours each time. I can't believe you hung in after having 20 of these. Wow! My neuro has suggested imuran as a possibility, but right now I am just having a MRI every six months to check progression. I feel so much better now than one year ago when I was on copaxone.