Baby stomach pains

[suzweasel]

I started my 3 week old on a bottle of formula a day, to give myself a rest from bf, but he now seems to have bad stomach pains and is having trouble having a poo! Any advice, is this normal?

Formula is much more diffcult to digest and different from breast milk hence the poo is harder and more formed, some babies get a bit constipated at first.
The stomach pains may be related to this or he may have colic.