Nursing - Prairie Grove,AR

That is kinda weird. This might not be it at all but how is his neck? When he's in your arms or laying down or is even held out under his armpits does he favor one side? Does his head turn one way most of the time? Some babies early on can develop torticollis. This is when their neck muscles on one side get tight. So they have a hard time turning their head to that side. This causes them to not want to nurse on that side of the breast because it hurts the neck. If he does have these signs just call your doc. They will refer you to a PT. They will just need to do exercises and stretches on the neck to relax and loosen those muscles.
My other thought is maybe you don't make enough milk on that side? Have you tried feeding him from the left breast first, then once he's sucking starts to slow down and he's getting somewhat full switch him to the right side. Maybe he just gets frustrated on the right side because he's hungry and it just doesn't come out as fast as the left side?

That, for me, was the first sign that I had an infection... Each time it was mastitis. He noticed the change in taste, before I felt discomfort or my milk turned turquoise.

For my sister, that was early warning she was getting another ear infection, Donny mum could get beer on antibiotics before it turned into a serious ear infection or double ear infection.

Nursing strike google it see if tht is what your going through

Not sure why, but don't stress about it too much. Some babies just reject or prefer one side for some reason. Might be the flow or amount that each side produces. He might be more comfortable lying on one side too.
My friend successfully nursed her first for 18 months and, from 6 months on, exclusively on one side. Her second is now also about 18 months old and nurses almost exclusively on the same side as the first.

I know it must be frustrating, but there is a good chance you can continue nursing as long as you want, even if he never really goes back to that side.

This isn't going to help, my last daughter favors my right breast. She favors her left when sleeping in car seat etc. we did exercises and she's fine now, 9 months. Even now, she'll nurse the left but not for long. So I have way more milk in my right....which is usually a cup size smaller so now they are equal ha ha.

it may be time for a doctors visit. You could have a problem. I would be safe and get it checked out and it could be nothing, but with him all of a sudden not going to that breast get it checked out.

Goof luck
T.