The short answer to this question is no!
Stretching has its place in helping to regain a normal range of movement in a joint. But in order for a normal physiological movement to take place in a joint there needs to be an efficient accessory movement.
Unfortunately it is not possible to carry out an accessory movement by yourself. So you can try as much as you like to stretch that stiff neck or back, and it may feel good at the time and maybe even give some temporary relief, but you will no doubt be stretching again hours later or the next day as things are not getting any better.
Fortunately there are several treatment approaches that can help to restore that all important accessory movement.
So if you are suffering with joint stiffness and things are not improving despite your earnest efforts at stretching, then consider the possibility that you may need help to restore the accessory movement in your joint(s).