I don't breath appropriately. Most of the time i hold my breath its like I'm tensed. When i was a child i started doing this when i was near people but today (40 years old) i hold my breath all the time even when i walk. When i am sleeping i breath appropriately. I have developed a lot of problems like Photophobia and Phonophobia . Is there any exercise that can make me breath appropriately?
Try to breathe mindfully; be aware of in breaths and out breaths and also be aware of the length of the breath more often. Make it so that there is a proper rhythm to it, and a habit.
Important bit is to combine it with mindfulness practice in a gentle fashion - stressing gentle.
On the other hand, how wonderful that you will be doing it mindfully with such purpose!
There is also a beautiful yoga in Dzogchen tradition called Yantra Yoga that is a yoga of breath; it is worth taking up classes for great benefit.