Lower Back Pain

Hi!
My rat's name is James. Hes the sweetest little rat, gives kisses, snuggles, and is very social. He has always been extremely active, and playful. He still is, but not as much today. He has been having problems cleaning himself, falling over after a few minutes, and here and there falling from climbing the bars here and there. I realize he is almost two, and has slowly showed signs of age, but today was the sign of all signs.

He came over to say hi while i was feeding and giving him treats, and he tried to crawl out and jump on me like usual, but when he got up to jump, he screeched, and sat back down and limped into his corner.

I think its his lower back, and when i went into investigate, his brother was very protective of him, and James snapped at me but then licked me. I think he didn't want to bite me, but he was in alot of pain. He took a few minutes and was fine, and came back out to see me, and was playing with his brother just fine. Is almost like its a pinched nerve in his lower back or something.

Does anyone have any advice for reliving the stress from his back? or treating it, or anythign i can do for him. Other than that, hes is perfect health.

Any help is appreciated.
Thanks