Wait, you have the hot set to 105F?? You will cook that snake. I keep all my boas with a hot spot of 86-88F and even then, they dont spend much time on the hot spot.
All the temps matter in each zone. You want 77-79F cool side and 86-88F hot side. The ambient can be anywhere from 77-80F. You need to give the boa a place it can get warm and a place it can get cool but not too cool and not too warm.