I am having severe dizziness when lying on my left side and when i start to get up. i have been on bp meds for 2 years. what could be causeing this.

Vertigo: Positional dizziness like you describe is likely to be secondary to vertigo from labrynthitis.

BPV Benign Vertigo: We have 3 small "stones" on each side of our head. They float in c-shaped tubes or canals. These canals are lined with fine hairs which then transmit the position to our brain. These stones and tubes act like the bubbles on a level a carpenter uses. If a stone "sticks" then conflict arises in our brain which makes us dizzy. Sounds like one stone on one side is the culprit.