Getting these scalp muscle twitches or spasms that are not painful but annoying. What could it be?

Depends on location. There are muscles that are attached to the scalp. The most prominent are over the occipital region (neck muscles) or the temporal region (temporalis muscles). It is likely that you are having some spasms of these muscles. This can be brought on by injury, pain, anxiety. Treat the muscles with pain medications, relaxation techniques, heat, massage.