If i go to er over a bad headache what testing will they do?

It all depends: In most cases a patient presenting to the er with a chief complaint of headaches will be observed ; given an rx ; send home. However, there are cases which are more severe or warrant further testing, and in such cases an MRI or cat scan maybe ordered. It's often up to the dr in charge of the er that day. A neurologist or pcp visit is less costly. Depending on the severity, use your judgment.

Headache: Depends on what the doctor thinks may be the problem.