What Causes Swelling In Feet, Ankles And Calves?

Hi, my feet,ankles,calves & lower legs up to my knees are very swollen & tender to the touch. Also have sharp shooting pains which feels like electricial shock /knife stabbing. When laying down. If lay on either side/hip it becomes unbearable. I soaked feet in Epsome Salts & have them elevated. Tried Ibuprofen & Tylenol massaging w peppermint foot lotion. Nothing is working. The takes my breath away. How to treat this & what causes it? Thank You for your help
Karen