Digestion problems

I think Mac is having issues with digesting solid food.

We started on baby rice and had no problems. When we introduced veges or fruit he started getting constipated. He'd go for 2-3 days without going then suddenly be screaming in agony as it all came out

Now he still only poos every 3 days or so but there is no pain with it.

But now, well for the last 3 days, when I try to feed his evening meal he throws himself backwards, arching his back and screaming in pain. Kind of like Reflux.
He eats his morning meal of fruit just fine but goes mental with his evening meal.

The way he is acting is indicating he has a sore tummy and I'm thinking he's having digestive problems, but what? And how do I fix it?

Will probiotics help?

All the doctors are closed until Monday but if I can find anyting to help him until then that'd be great.

TIA

New quantities but he throws a spaz at within the first few spoonfuls. I always introduce a new food on it's own, then a few days later will mix it with a food he's already familiar with.

The poo thing has been an issue for the last 2-3 weeks since we properly started introducing foods rather than just rice.

I do wonder about the teeth, we Bonjela him every night before bed but did wonder tonight if I should try doing it before his dinner. Gross taste though

He is always keen for the food though. I hold the spoon away from him but where he can see it, when he's ready he opens his mouth and I put the food in and NORMALLY he swallows it and fusses for more. But he's started spitting it back out, arching his back and crying. But then once he settles he opens his mouth again for more
So I take that as meaning he's hungry, he wants the food but something is wrong and it's stopping him from being able to.

He does have Silent Reflux but since I cut out dairy out of my diet (he's BF'd) he stopped refluxing BUT I can relate his actions of the back arching to how I react if I get heartburn.

I'm also confused cause he eats his morning meal of Apple & Pear with Baby Rice just fine. But come the evening meal (which is a range of root veges such as carrot, kumara, parsnip, etc) mixed with baby rice he doesn't cope.

Might have to try finger foods or something. Or like Mel said go back to scratch again.