My LO is 2 months and is on formula and bf. He had not been pooing for 3 days is it normal? He keep make shitting sound I don't know should I give him a bit of plain water..

Actually when they are two months old they shouldn't get constipated so easily as they have not started on solids too. Consider to change his formula. What brand is he on? I will give a little Plain water but not too much