I stopped playing for more than 12 years for different reasons. I bought a used bass on Friday and have been practicing and doing lots of exercises and started grooving on my own, it's lots of fun but it's going to be a process, as I have to relearn loads of chords and scales. But it's coming back faster than I expected. First off, the right hand still knows pretty much what to do. Second, I still can place notes on the neck pretty fast and when I looked at a score, it started to come back fast as well. BUT the left hand, my god, it's going to be a slow process. I still remember lots of my old tabs but all the dzzzt! and squeeks! sounds argh! it's aggravating. Who has been through all that and how far did you go? Did you manage to get it all back and even improve from when you stopped? And what sorts of advices do you have!
It's apparent that you still remember how to play, but you no longer have the strength in your fretting hand, and that will come back with time. I'm still in the stage of being stopped, I still have some gear and I still noodle a bit from time to time. My left hand isn't what it used to be, but the rest of it still works.
Don't worry. Just take it slowly and if it hurts stop playing until the next day. I restarted on double bass after a break of 8 years and started gigging after about a month of practice. First few gigs were a bit painful but it's getting better now. The hardest was the physical side of playing - all the stuff to do with what to play (notes, groove, harmony etc) was second nature. Good luck.
I gave it up for 20 years. My old band decided to do a reunion gig back in 2000 and I've been playing ever since. When I picked up my bass after those 20 years, it was like starting over. For me it was just sitting down an hour or two a night and trying to get my fingers to work, my hand to stop hurting and trying to build up those callouses. Practice, practice, practice.....