Hello, I m an 18 year old female and have noticed a change in my back, I don t know if it s from too much heavy lifting, but I find myself laying or sitting down a lot more than usual because my back feels under pressure or unsteady, and it seems to accelerate my heart rate a whole lot. I just feel the urge to sit down which is unusual for me. And for some years now I ve been getting temporary disorientation and vision loss when standing up, after sitting for a while. I m not sure if it s hypertenstion, 3-4 months ago my blood pressure and blood tests came back fine. I don t know what this could be about.