Should I start going to the gym? Do any NEETs here lift weights or do cardio?

Hi, I've been a NEET since February 10th, 2021. I mostly stay at home. I broke my back in 2017 so I have chronic pain. I can still function fine though. I wonder these days about going to the gym to start lifting weights and doing cardio. I'm already strong from working in construction for 10 years before I was a NEET. However, I'm overweight and smoke weed and cigarettes a lot. When I was working I would walk a lot too. Usually a minimum of 10 kilometers every day. I think my record was \~30 kilometers in one day. I wonder if my chronic pain would improve if I started lifting weights. I'm already really strong I just need to try not to lose the strength I have already. I'm not interested in getting stronger. Just to maintain strength. Right now the only physical activity I do is walking a few kilometers every few days. For example today I walked 7.16 km. Yesterday I only walked 2.27 km. I can't run for fuck because my lungs are fucked from cigarettes but I do alright going slow or medium pace on a bicycle. Maybe I'm thinking out loud. I don't know. There's actually a decent gym about 700 meters from my home and it costs $4.50 for a drop-in session. I might go check it out soon. Anyways, any NEETs here lift weights or do cardio?