Is it too late to sue my previous employer for back injuries 8 months after I left?

Question Details:

I still work in the same shop that I did before;it was just bought by another company shortly after I left. My pain and problems started about 5 years ago and have steadily gotten worse over time. The problems stem from standing/bending over a lathe and grinder all day long for 12 years. I have seen a doctor and been treated for this. I paid for it out of my own pocket previously and it is very expensive even with insurance. But the treatment worked for about 1 1/2 years and is now starting to wear off again. I had a nerve block done on my lower back and it worked well but isn't a permanent fix. Important Notice