Yes, it's bad. Potentially life threatening. You are not keeping the snake warm enough. He needs a warm end of 85F, 24 hours a day, and a cool side of about ten degrees less. Putting a heat lamp on him for a few hours a day is not sufficient. Putting him out in the sun is not sufficient. He needs an adequate cage with a UTH and a thermostat or rheostat.
First, you need to get his housing straightened out, or you are going to kill him.
Then, you need to follow the regurgitation protocol. Do not feed him for 8-10 days. Get some Nutribac from Kathy Love
http://www.cornutopia.com Sprinkle that on his food when you start feeding. He needs to have a pinky head _only_ for the first meal, and then gradually work back up to a small pinky. But don't even bother feeding him if you can't provide a temp warm enough for him to digest. In the 80's, 24 hours a day.