Breathing exercises or breath control

As we're a group of people who are interested in singing, I was wondering whether you all do deliberate breathing exercise to expand your singing abilities.

My breathing exercises are limited by 2 factors. One is the time of the year or allergy season for me. Being stuck in an area that has me stuffed up for a good portion of the year, I exercise to breath by reaching for allergy medicines. Something I'm going to have to do in a minute as my nose is flowing and I look like I'm crying right now. Here Kleenex, kleenex.

The other factor is that due to a bone spur that's developed in the thoraxic region of my spine, I have a nerve problem that constricts the area around my rib cage. My tendency is to draw shallow breathes because of a tighten belt feeling. Or I make myself take deliberately deep breaths and fight my way past this sensation. Because of these 2 problems, I don't have the breath control I once had and it got me to thinking about breath control exercises and singers.

So anyone have any good breath control ideas or exercises to share? Please say yes, as I'd really love to hear what you do to expand your lung capacity.