Because it's normally dry as well, you can't just comb it out of its matted state. It would cause lots of breakage and be quite painful.
There's a simple solution:
1. Spritz your hair with water. I normally add my essential oil blend, Neno Natural's Hair Growth Stimulator, to my water.
2. Don't try to lift the matted hair out immediately. Put a shower cap over your head then go about your business.
3. After about 15 minutes, the hair will be soft enough to deal with. It will feel completely different. You can spritz more water onto it if you like. Finger comb it and you're good to go.
Simple as A, B, C. Or 1, 2, 3 in this case.
One of my friends gave up on being natural because she simply couldn't deal with matted hair and as the only natural haired black person in her boarding school, there was no one to turn to, ah well.