Might consider a more comprehensive set of labs if the usual set turns up OK. The Female hormone panel is great, but this goes beyond. If you have good insurance, get your doctor to prescribe, otherwise, PrivateMDLabs.
However, it cannot be the testosterone, it does not become active until it seperates from the ester, which happens over the course of days. Virtually no testosterone is being added in the first few hours with Testosterone Cypionate - the drug has a half life of about 7 days.
If you take 50mg, you are getting 1/7*1/2 of the dose = 1/14*50=3.6mg per day. (I know I'm straightlining a curve, but the point stands). Of course, the Cypionate ester itself attached to the testosterone hormone has a weight, so actually it's more like 2.5mg per day of actual hormone going into your system. That isn't much at all.
I'm gonna go with either allergy or psychology as well. If it is a needle thing, you could switch to subcutaneous injections, the science is pretty settled that it works for testosterone replacement therapy (TRT) size doses.