My cat keeps getting in and out of the litter box over and over again.?

Exactly what Kristen said, your cat could have cystitis. It is very common in male cats. If he does have it you will need to put him on a special diet for the rest of his life.

He is probably in a lot of pain so get him to a vet right now !!

This is a bad sign. The cat wants to pee but can't because the urethra is blocked. It's known as FUS, feline urinary syndrome, and it's dangerous. The urine can't get out, the bladder lining starts breaking down and bleeding, the kidney function shuts down and the cat dies from blood poisoning. The longer the cat is blocked, the more damage is done. Getting the cat to the vet asap (and yes that does mean asap) is critical to stopping the problem. Cats can die in 24-48 hours with this.

Is his back fur spiky? Is he crouching instead of sitting or laying? Is there only a tiny wet spot or a drop of blood in the litter? Is he crying?

Any of these are danger signals. Be on the vet's doorstep tomorrow morning when they open and have the cat looked at immediately. The longer you wait, the more chance your cat is going to not make it. This is an extremely painful thing for a cat to be blocked like this.

For a male get him to the vet NOW!!! My brothers cat Clarence had the same problem, he kept trying to go but couldn't and unfortunately my brother waited the weekend to see if he would get better, but the cats system got poisoned and he didn't make it. Something about crystals forming in his system and unable to pass urine. Not trying to scare you but get him in right away so if he does have an infection you can get it cleared up. Male cats are more prone to this. Good Luck!

I think you are right to suspect a bladder/kidney problem as it will feel a continual need to urinate and it may be confused as to what's going on. The kind thing to do would be to take it to a veterinarian to have it tested. Your pet is obviously upset and confused.