17 months post op from PRK I have excruciating pain 3-4 mornings per week when I first wake up. What can I do?

I use eye drops every day throughout the day. Sometimes my eye pain jolts me out of bed in the middle of the night. They keep burning for at least 20-30 minutes & i cannot lay down as the pressure is too much. My eyes are swollen in the morning when this happens. I'm almost afraid of sleep because this eye pain is as severe as when I was first recovering from PRK. My eyes are not red throughout the day, they just constantly feel dry. Any suggestions are welcome. I am tired of this happening.