I have phantom pains in my coccyx that occur in certain circumstances.
They can range from dull aches to synapse-searing agony.
Endless fun.
I would get that checked out if I were you! Did you hurt it at the dunes?
I get ear infections fairly frequently and once I had to blow my nose and both ears popped. I saw colors for a few seconds like I was just hit in the head and was hunched over in agony for a good minute.
I cant leave out the few times I've been credit-carded (when one end of the board is facing the ground and the other is up in your groin and then you land) trying to attempt a inward heelflip (Skateboarding)
The first few days after my first day of snowboarding were filled with stiff pain.
Getting scorpion-ed while snowboarding without a helmet.
And last but not least smashing my face into the steering wheel from a car accident I was in a few months ago which ended up breaking my nose.
Just to name a few 
Dirt biking.
Was going much faster then I should of, hit a huge rock in the road that I couldn't see because of my helmet.
Got thrown off the motorcycle and landed on my side on top of a large rock/boulder thing.
Cracked 3 ribs and my side was a weird red/yellow/purple color for about a month and a half. Didn't really get back to 100% for about 5 months.
Ive been dirt biking since I was twelve and have yet to have anything where I couldn't get up and brush off the dirt (hee hee) .