One thing to remember is not to work too hard when doing Somatics exercises. I know that is really difficult for many of us who have been brought up to think that there is no gain without pain, and that extra stretch will bring more results. But with Somatics the opposite is true.
The extra effort can send already tight muscles into spasm. So take it easy; work at 50% less effort. If you are straining or shaking when you do the movements you are working too hard. Its often a good idea to gradually decrease the effort during a movement and really focus on the feelings and muscle release to complete rest. And do remember to pause and relax fully between repetitions.