Probably ask him if he's okay, but almost like slowly bring it up like: it's awesome when we get to have these conversations together, since you seem to be busy a lot
It's worth considering that if you need strangers to tell you to talk to your boyfriend when something seems wrong...you might not be ready for a relationship.
Also people have lives and there's nothing wrong with someone taking an hour or two to respond to texts.
so lately its been hard to keep a conversation going with my boyfriend; basically im always the one to start convos, and he doesnt reply for an hour or two and if we do get a convo started it only lasts, 20 mins- 30; leave suggestions on what i should do in the comments please