I wouldn't assume it was about you. When something like this happens it is easy to think that it might be our fault, but thinking such doesn't serve us well. The fact of the matter is you don't know why he blocked you, but thinking it's your fault is only going to make you upset without getting any real answers.

As for whether you should message him or not, I think that's up to you. Personally I wouldn't, if it were me, because I believe people show you where they're at with their actions and it's apparent he's not into hearing from you right now, but if you want to send him a message saying you miss his friendship and you wanted to make sure he knew you hadn't ghosted him and you're thinking about him I think that's fine. I would suggest, though, keeping it short and sweet and, if he doesn't respond, take that as a sign to move on.

Good luck and feel free to PM me if you need anything else.