Fastest....cover the burn with Noxema cream, in the jar. Cools instantly and kills the pain instantly. Throw on loose cotton clothes, an oversized T for example, yes it will stick to the Noxema, but you will be able to lie down and rest. Drink a lot of water, avoid the sun, if you must go out, spray yourself down with a high SPF sunblock, cover your head. One draw back to Noxema, it leaves a waxy white film or residue on the skin after a few hours, which can be rubbed in like a lotion or gently rinsed off the next morning in the shower.
Aloe vera gel for sunburn is good, but doesn't always relieve pain. For severe pain, use the Noxema, generously, then take a Benadryl for allergies tablet, again, drink lots of water. The Benadryl will help decrease the swelling and pain in the burn. Rest, plenty of fluids, and keep reapplying the Noxema until your skin feels better, after that use your favorite dry skin lotion. Try to avoid lotions at first, as they tend to make a burn really sting. Another quick fix for pain, soak your skin in Bactine, the clear stuff you put on cuts...kills pain quite effectively in a pinch. Good luck.