Just got dumped via text, how can I find out why?

Honestly, just leave it alone. He's an and if he hasn't responded by the first text then just stop texting him. He'll be more keen to responding to you if you left him alone. You continually texting him is either annoying to him or he may find it pleasing to be pursued by you. Don't text and see what happens in a few days, and frankly it's probably best to just let it go all together. He's an ***, just forget about him.