I have developed the same condition after getting sunburned at the beach two days ago. My burn is concentrated around my knees and on my thighs just above the knees. If I have been moving around for a while, it is okay. However, when I get up from a sitting position -- or from lying down -- the pain is SO excruciatingly intense that my legs almost buckle and give out from under me. The skin, like yours, feels VERY tight around the area of the burn and I literally feel like screaming out in pain every time I stand up. I have been rubbing an aloe lotion onto the affected area, and that seems to help a little bit. I have also been told that moisturizing creams -- or hydrocortizones -- might be useful. Either way, I am hoping that the pain begins to decrease SOON. I got this burn on Tuesday, and as I write this post, it is already Friday morning and I am still in a GREAT deal of pain. Good Luck.