I've just been told by my doc that I am producing double normal prolactin hormone I have an MRI next week but I've had a head ache every day since dec?

Possibly related. Prolactin is produced by the pituitary gland, part of the brain that sits in a recess on the bottom of the skull. Too much prolactin may be due to a type of non cancerous tumor called an adenoma. A pituitary adenoma could cause persistant headaches. This is all very speculative, it is important to get the MRI to help claify if there is a pituitary porblem. If not, more evaluation is needed.
Prolactin level PRL. Elevated prl levels can be caused by a pituitary gland tumor, hypo-thyroidism, antidepressants (ssris & snris), antipsychotics, emotional stress, and pregnancy & lactation. If a tumor is large enough, it can press on the optic nerve crossing & produce visual changes, nausea & vomiting, & vertigo. The MRI is to check for such a tumor. There are meds to shrink the tumor, or if needed, surgery.
Might be migraine. An elevated prolactin level can be caused by a small tumor in the pituitary gland at the base of your brain, or commonly from breast stimulation. The MRI is to check for the tumor. These type of tumors more commonly cause visual changes and not headaches. It may be worthwhile having a good eye exam, trying meds for headache (such as Excedrin migraine) and following up with your doctor.