After spending a week doing a bit of riding (probably close to 100 miles) I have come to the conclusion that my handlebars are definitely too low.

How did I figure this out? Well ... my lower back is quite lame and I can't walk after getting off of the bike. After experimenting around with some wood blocks and duct tape (raising where I have to hold), I narrowed it down to being handlebars that are too low.

When I got the bike, Raleigh M50DX 2004, I had the bike shop raise the handlebars as far as they could and stick "shims" in it. It worked for a few years but not anymore.

Are there any aftermarket handlebars that would work with my bike?

And are they dependent on the front fork? I will be getting a new front fork for it soon.