Is my ball python too Hot?

I have a 30 gallon breeder tank. its 36" long x 11" wide, by 16" tall. Inside lives my 3 year old, 3 1/2 foot Ball Python, Edgar. Its winter now and my apartment gets quite cold. I origionally had a 4 x 6 heat pad and a 60 watt 'Red Night bulb' that i used on his basking side or the tank. Then, I noticed my BP was staying pressed up against the warm side of his tank. So I bought a bigger heat pad and a 150 watt ceramic light. This makes his hot side about 95-105*F. BUT HE STILL STAYS ON THE HOT SIDE OF HIS TANK ALMOST ALL DAY AND NIGHT. The only time that he moves around is for about a 1/2 hour after i spray him...then back to the hot side. So here are my questions: 1) Should i turn the heat lamp off at night (even though he still wants to bask? 2) Should i leave the heat lamp on and just turn it down at night (I have a temp adjuster knob)? 3) Is it important for a snake to go though a 'cold season'? 4) Does this snake need to see a Vet?