Things started with dizzyness when I would st up, then noticed pain on my neck, kind of stiff. Pain started behind my eye then I started getting sick to my stomach. I have sle, hypertension, and stage two kidney disease. Also had mild stroke two years ago.
The dizziness when you sit up can be explained by or tho static hypotension.  It is mostly due to the antihypertensive meds you are taking, fluid deficit status are more rarely autonomic dysfunction caused by sleep itself. The blood pressure falling transiently when you move again gravity i.e. Sudden sitting or standing from sleeping position explains your symptoms.  So I recommend reviewing your medication and try finding the culprit