Turtle making hissing noises for a couple hours?

by Jaime
(Tucson AZ united states.)

I have a russion tortis. I have recently changed his bedding from pellots to a bark. His dish is a little big and it is hard for him to eat out of it. So I put his food on the bottom of the cage so he could eat it. I am a little concerned that he may have eaten a little piece of the wood and something is stuck in his throat. He is making these weird noises. It sounds like he is hissing but he is in his cage by himself. I feed him once a day. It has been really cold here. In the 60's to the low 30's so its been a little cold for me to sit out there with him while he runs around. I am also a little scared that he might be gaining a little to much weight for his shell. But im mostly concerned with the noises that he is making. What do I do? how do I know what it is and now do I help him if he is in pain? I put him in the tub with just neck high warm water to see if he would drink some of the water. He opens and closes his mouth like he is eating something but he isnt. Is this serious? Please let me know right away.