Guitar Problems?

Can pickups "wear out"? I have an Epiphone SG Special. It has two open coil humbucking pickups. I play it through a 15 Watt Peavey Transtube Blazer Amp. At first it sounds fine, but then it starts changing pitched, and it has alot of buzzing when i play it clean, and it makes some weird noises. I tried it in a different amp, and it pretty much sounded the same just not as noticable. It hasn't done this until i started playing for like 2-3 hours a day. What is wrong? Do I have a bad connection, or do i need new pickups? Please help!