Does anybody else's baby have trouble with rice?

I've been feeding my six month old son solids since he was 4 months without a problem. He loves sweet potatoes, green peas, apples...basically anything I put on a spoon. But, he can't tolerate baby rice. I started feeding him that before I tried food & he ate it fine. But a few hours after, he became very ill, projectile vomiting & screaming in pain for about an hour. Horrified, I refused to give him rice for the rest of the month. His doctor told me it would be okay if I started solid food & skipped rice. At 5 months I tried rice again...with the same results as the first time. I did some research & found that a lot of babies have had problems with grains because although they're bland, their stomachs can't actually handle digesting them until they're 3 years old. I don't know how true that is & I haven't tried other grains, mostly out of fear because I hate seeing my son so ill & in pain. Has anybody else experienced this? Did your child grow out of it? Just looking for some similar stories.