I've ran three "experimental" f-conversions from researchkits.com but with the recent bad publicity I've heard on this and other boards I went with universalkits. Problem is my research subject is experiencing pain in the entire muscle group that the product is injected into. There is no redness or real pain around the actual injection site and no lumps or discolorations. The pain in the muscle group subsides in a couple of days but this is a very strange experience for me as I've never had any problems with past experimental conversions. What could cause this type of reaction?