Stop sleeping on the fucking couch, this is pretty simple. Couches aren't designed for a good night's sleep, they're designed to be sat on by multiple people for watching TV or w/e. Some might be better to nap on than others, but still they are not meant for sleeping. You specifically called out your neck. I've seen many people sleeping on couches, with their neck bent at almost a 90 degree angle as they use the armrest area as a "pillow". Then they wake up and wonder why their neck is all fucked up and their body is sore. Get a bed or a futon or something. Use a new pillow. Continue stretching regularly. I would bet my life that most of your problems mentioned here will go away within 5 days if you get off of the goddamned couch and into a bed like an adult.