It's different, but as an example, I injured my back (i don't really even know how) and was in intense pain for approximately 8 months. You know that feeling when you burn your hand on something? It normally last 5-15 minutes, well it was like that, but inside my lower spine all the time, for a solid 4 months...and then in duller state for another 4. I am still struggling with pain from time to time, but i'm once again able to sleep a full night (something i couldn't do for around 5-6 months), do physical things and not regret every movement. At the start of the injury, i was probably the fittest I've ever been, but now i'm probably the least fit i've ever been. It's seriously sucked. Who am I kidding, it still sucks...coughing hurts...but its improving and that gives me hope that one day it'll be 'normal' again.
Until you've had a long term injury, you have no idea how to sympathize. Right in the middle of this i had a close friend get upset with me that I came over when I knew he was painting, and didn't offer to help. I was frustrated he even considered it a possibility, i was struggling to sit in a car for more than an hour, how was I going to paint a wall or ceiling? People just don't understand.
To everyone suffering with something that inhibits their ability to enjoy life, i'm sorry but wish you the best. To everyone looking in from the outside, assume its 10x worse than what you see and reconsider your next move.