Actually, i may have found the problem. His basking spot is way under what it should be. I hadn't checked the temp in there for so long and I had replaced the bulb with a different one, but lower wattage.
His basking spot was only 100 degrees when it used to be around 125-130. I also had 2 hide spots for him, but he never used the one of them, so I took it out to give him more room to roam around in. His current hide spot consists of flat cinder blocks stack on one another in which he can squeeze in and barely turn around in the space.
Tomorrow I will pick up a higher wattage bulb and see if his "laziness" improves.
Also, i asked about his throat gulping thing he does, is that an indication of anything or is it regualar monitor behaviour?