What Causes Swelling In Fallopian Tube?

i m 26 yrs old, irregular periods and married for 4 yrs but not concieved yet, i had undergone laproscopy on 11/05/2011 and my doc told me that there is no blockage in tubes and everything is fine in uterus but there is swelling in tubes....i want to know what is the reason of swelling in tubes?.... how can it be rectified? my doc recomended a 12 days course(Doxytop And Azee) on 25 of every month for 3 months in order to concieve...