I always have gas after i eat.is there anything i can buy to help relieve it?

im not talking about burping.but flatulence all the time.when i first wake up in the morning im fine.as soon as i have a coffee or even a tea i start.it gets worse after breakfast and lunch and dinner.im not over weight,im active because of my job and am not taking any meds.i have tried leaving milk out of my diet that didn't work.i did the yogurt thing that i saw on tv that's suppose to help with digestive system and that didn't work.any ideas?been to doctors and he told me the above like the milk thing and yogurt thing but like i said it didn't help.