I stopped taking Synthroid after 4 days due to extreme joint pain...

I stopped taking Synthroid after 4 days due to extreme joint pain (9-10 on a scale of 1-10), confusion and emotional roller coaster that's very unusual for me. Like most others, my doctor and a specialist were of no help. I looked online and found that joint pain can be a symptom of hypersensitivity to inactive ingredients. I discovered that Levoxyl doesn't have the side effects for me that Synthroid does -- in fact, so far I feel great! I suspect I had a hypersensitivity reaction to an inactive ingredient because those ingredients vary greatly from brand to brand. In fact, I wonder if folks who get better with Armor are simply getting better by getting off Synthroid? Maybe others who may be having trouble with Levoxyl could have better luck with a different brand? It's such a small thing to try, just changing brands, before going through extremes of changing doctors, taking handfuls of other medicines, or suffering through unreasonable side effects. Has anyone else had that experience that switching brands cleared up their side effect problems?