The best way to get rid of your stiffness and get your body awareness back is to get to know your muscles, bones, heart, etc, and become aware of their existence again.
Feel them, by dedicating a few minutes a day to your body. In all my years of exploration I have not found anything that works better for most people than Yoga (done in silence). But any slow, silent and stretching movement could do the same. The point is to feel, every movement, every muscle - feel which ones are active and which ones are relaxing, and avoid any disturbance to that feeling.
Most of our stiffness comes from traumas experienced in childhood before we had the capability of expressing them or understanding them. The trauma was easily 'stuck' in our bodies, with a lowered flow of humours and energy. Any insignificant happening could have blocked the body and most of those we aren't even aware of.
For unblocking stiffness in your body more quickly, you can take away as much as possible of what is 'censuring' you from getting to know You, both your body and mind, i.e., to detox.
Eat clean and healthy vegan food, get rid of toxic chemicals, etc, and for your mind, seek environments where you feel loved, not just tolerated.
Change friends, partners, job, even family if you need to, but don’t stay in environments where it is required of you to like things you don't like, or dislike things you don't dislike, or to be someone you are not.
You can always come back to those environments when you got most of You back and resist outer pressure or even understand and embrace the pressure. But remember where there islongterm pain there is no longterm gain. Equally there is not always longterm gain in short term pleasure. Read more about how to get rid of anxiety.