constant gas and bloating

For the past year and even more I have been experiencing constant gas and a bloating feeling throughout the entire day.
I do not eat a lot. I exercise 4 times a week for 90 minutes each time- Yoga Plus 2-3 times a week weight lifting.
I do not consume sugar nor do I eat sweets. I do not eat late and I go to sleep around 9:30pm every night.
I do not have pain, only persistent bloating and sensation of trapped gas is if I need to relieve myself and when I do all that happens is I release gas.
What could be the cause of this and what tests or evaluations should I consider ?