problem with ecosprin av75/10

i have undergone aortic valve repair surgery on 20/12/2012. Since then I am taking ecosrin av 75/10 till now. But since 1 yr ago, I am facing problem of constipation and gases. my stomach could not be emptied completely. I have to face gases through out the day. Due to these gases i face cramping in my legs also.

Can anybody suggest me remedy