9 week old - sudden painful straining

[fatsowhale]

My 9 week old DS has had a bit of colicky/straining-type crying in the evening, usually between 5-8pm. It's eased off over the last couple of weeks except for the last 2 nights he has been totally disrupted, screaming in pain between feeds, up for more of the night than usual. It resolves itself when he eventually poos.

I'm EBF and the only thing I've done differently in the last few days is start putting a few chia seeds in my breakfast cereal. I don't bother to soak them - could this be it?

Any ideas gratefully received.