stomach pains after every meal

Abigail
Just wondering if anyone else has experienced this or knows the cause of my stomach pains. Whenever I eat, whatever I eat I get stomach pains. Breakfast, lunch and dinner. It doesn't matter what I eat, cereal, sandwich, soup, salad, meat literally everything gives me stomach pains. After a big meal I occasionally get a tight chest too. I'm not over or underweight. It seems to of got worse since having my son 6 months ago and has got to the point where I avoid eating. Thank you for any advice