B.P.
i work in the medical field in a specialty that sees these things so by no means up front i am not giving you medical advise but wanted to provide some information. The pituitary lesion may be a pituitary tumor (aka pituitary adenoma) but the MRI they will get is typically dedicated to give better detail to the gland and tumor. The endocrinologist usually gets a bunch of lab values to determine if the tumor secretes prolactin, a hormone. If so, sometimes they can provide medicine that can shrink the tumor if they determine that it's a prolactinoma. These tumors typically can be monitored with yearly or however decided by the provider, followup MRIs to watch it. They typically don't pose a problem requiring removal unless they are of significant size and push on the optic chiasm, or the area where vision is involved. Sometimes patients are referred to the opthamologist to get formal visual field testing to determine if there are vision issues that may not be readily detected by you. Headaches and dizziness are not common findings of these types of tumors in my experience but it can be frustrating if no one can give you an answer. I hope this was a little helpful.