The nightshades contain solanine. If you search "solanine" on the web or on this forum, you'll find some of my searches and posts. Solanine is thought now to accumulate in humans and is very high in nightshades. Giving up potatoes, has really helped me. Who would have thought? Wish I had known that 20 yrs ago.
Some tomato is okay for me, but concentrated into paste sauces will cause me to burn, most of my burning is on feet.
There are sites with histamine containing and releasing foods. Tomatoes are one;
http://neurotalk.psychcentral.com/thread161714.html
My husband has always avoided tomatoes because he says they make him itch/tingle.

Another thing that is very very damaging is MSG. This inorganic salt of glutamine stimulates the pain receptors NMDA. So it is best to avoid it as much as possible.

Different people react differently to foods. So it would be a good idea to do eliminations on various groups.
Soy
Casein
gluten
nightshades
Even Onions/garlic (lily family)

The problem with birth control is that it is a constant hormone provider, whereas we women cycle estrogen. Estrogen peaks at day 14 or so and then drops again. The doctor who did my EMG of my arms, back then said the hormones are high during pregnancy and make carpal tunnel much worse. Once they dropped, about 3 days after my son was born, my hands improved dramatically. And I could hold a pencil again, etc. I was very disabled by the CT from the 5th month until delivery.

I think the only way to know about the BCs is to stop them and see what develops. I never took BCs or any menopausal hormones either. Back in the days when they first were introduced I took them for about 2 years(they were stronger then too), and had fluid retention and elevated blood pressure. So I stopped them. I was in my early twenties then and in good shape, and horrified by my side effects. It was not a difficult decision. I had started with an estrogen only one, that had progestin added the last 7 days...C-Quens was name. They worked ok. But then the FDA got into a snit about tumors in Beagles from them, and took them off the market. I was forced to use Lo/Ovral, which was a horrible failure. I blamed the progestin for my troubles, because all the BCs then had progestin in the whole course.