GP Prop is relatively painless. Naps has that MCT oil carrier down to a science. I never had any pain with any of his products.
However, I am a little puzzled by your list in the opening post. I mean, orals are going to be the least painful of all. Unless you have Barrett's esophagus. Then they will cause pain and burning.
Basically, any gear can cause pain. It depends on the process and chemical/solvent/carrier ratio. As a rule, the "heavier" the molecule (cyp, enan, and other long acting) are generally less painful than the shorter acting versions.
