When I was on Celexa, a sister of Lexapro, I would get ticks and switches. It eventually went away once I was fully on the medicine.
It also might be treatable with magnesium supplements -- ssris often interfere with magnesium metabolism, and sometimes cause muscle cramps, twitches, etc. Magnesium citrate is a good form if that's what's needed.
Yes they can cause temporary movement disorders such as akathesia or dystonia. Those are not dangerous but can be uncomfortable and can be treated with a side effect pill. Speak to your psychiatrist about this.