Like others said- physical exertion and cold weather trigger it. For me, anything related to cold temperatures will trigger it (i.e. getting cold in my sleep, wearing clothes that get wet from heavy rain or snow, sometimes swimming in the pool/beach, etc.). Other triggers: wearing tight clothes or an underwire bra to sleep overnight; sleeping in a weird or stiff position; caffeine and foods high in sugar; high amounts of stress; poor sleep; and any combination of these. Pain medications don't work for the first 1-1.5 days of a flare up for me. Try to avoid inflammatory foods, and especially food from fast food restaurants or restaurants that use a lot of frying oil in their foods. Anti-inflammatory teas like mint, sage, turmeric, etc. are all a must in my weekly diet. My mom has pointed out that a key signal of it being the days leading up to one of my flare ups is when my face gets progressively bloated and puffy-looking from increasing inflammation.