Issues with my 4. 5month old infant.

My daughter who is 4 months old has started something new... she tends to strain a bit while passing urine.. otherwise seems healthy apart from colic pains ... no temperature so far n seems active plays laughs n all... she is kept in diapers we use poko pants the 10hr absorption one n the diapers are well soaked with urine changed regularly... only concern is her occasional straining to pee...has anyone faced this?? Also she doesn't pass a stool daily maybe once in two or three days n has always been coliky since birth.. for which she is on meds when she gets those episodes but due to which we hv to reduce her feeds .. ideally at 4.5months she should be having up to 30scoops of lactogen in a day but bcos of this she can only take a maximum of 18scoops n a day anything more leads to colic pains.. pls advz me on these issues ... Thank you..