There are a few different things that may be going on here. Before I dive into them, I do want to say that it's highly unlikely that you can't experience pleasure. Our brains and bodies can get pleasure from all sorts of things. For instance, if you read through this article, you can see ways in which we often experience pleasure in our daily lives: I Feel Good: Pleasure and Fulfillment
. If you truly don't feel any pleasure or enjoyment from anything (food, taking a bath, seeing a picture of a cute animal, etc) then that might point to a larger issue.
With masturbation, can you give me a sense of if you're mentally aroused when you try it? Or is it more that you're going through the motions with your body but your brain isn't super engaged? Too, you mention you've tried a lot of experimentation, which is awesome, but nothing has felt good. Can you take a look at these two articles and see if there are things in them you haven't tried? Going Solo: The Basics of Masturbation
, With Pleasure: A View of Whole Sexual Anatomy for Every Body