it is not usual, but also not really unusual!
What I mean is, I think a lot of us have experienced it, and sometimes it is a matter of working out what YOUR child needs. But if you can't work that out and it continues, it may be a sign of something.
Possible causes - reflux, milk intolerance, wind, overtiredness.
So, I would try feeding him slightly more upright (I never fed babies lying flat) winding him well in the middle and at the end of the feed, trying him with a dummy, if that helps him to comfort suck.
When trying to settle him, try gentle rhythmic movements, eg patting his back. try different positions, over your shoulder, face down on your arm etc.
When he is crying stay with him and keep making soothing noises and movements.
Have a think about when this was in relation to food, so was he hungry, or had he just fed. If he is pulled legs up to chest, then it is porbably his tummy, either wind or discomfort of some sort. try gentle massage circles on his tummy too.
If it keeps repeating, film it, and then go to GP and show them the film.