Everytime I take this it gives me the worst sore butt I have ever expierenced to the point I can not sit down. I have tried three different times thinking it was the way I did the shot, but I believe it something else. This has a gray stopper and I have read somewhere on this forum that if stoppers are gray it's probably fake, is this true? Please take a look and I appreciate any info. This is my first post so thanks for your help.