I am 7 weeks pregnant and was told i may have a tapped nerve a few weeks in my side but i keep getting a spasm in my left side head at the back?

See an OBGYN: Because you are pregnant and are going through active hormonal changes you should see an obstetrics specialist about this pain. It may be a simple muscle spasm as you say which will go away on it's own or with hot / cold compresses. It's tempting to reach for headache and pain medicine but do not take anything until you speak with an obstetrician first as to what is safe to take in pregnancy.