Dizzines, Soreness And Swelling In Back. Vitals Normal. Need For Concern?

Hi Dr. Samuel, When I woke up this morning after only a while I felt too dizzy and fell down. I can tell that I did not faint because I could hear everything around me. It went on for about 10-15 minutes. I went to the emergency and had all my vitals tested and it all looked fine. It was my first day of period and doctor felt that my dizziness might have to do with that.
But this evening I could feel soreness in my back...just below my neck. I can feel the swelling too. It pains on touch. I might have injured my back yesterday night during sex. I had slight dizziness after that but I ignored it and I did not mention this to my doctor this morning. I am not sure if I should be concerned about this and if my spell of dizziness has anything to do with the swelling in my back.
I am feeling quite okay now and did not have any dizziness after that morning spell. Please suggest