Hi, I am experiencing dizziness when I lay down on my back. Just wondering what I should watch for before I become concerned. I am 70 years old, in good general health except for obesity. I walk 35 to 55 minutes a day, and recently completed my annual physical exams. I did have a chiropractic session this morning for a frozen shoulder in addition to physical therapy yesterday for the same condition. I am currently drinking water in case I am dehydrated, and took an aspirin as a precaution. I normally do not take aspirin or other OTC medications. Thank you,