[cypher]

What's the temperature like where you are jojono7?
If it's hot then it's possible the heat may be causing this, if not then it does sound as though he's unwell & you need to get your vet to check him out.
Have you checked to make sure his water bottle is working ok, if he doesn't seem to be drinking too much he may be dehydrated & that could cause him to get constipated.
It's very difficult to guess what the problem may be but your vet should be able to help him.