My son is 13 months old and he throws up like, when he cries hard or sometimes with thicker foods. I'm not sure what's going on?

Delayed emptying. He may have slow emptying of his stomach so when he cries or has thicker foods that are hard to digest they sit longer and any bearing down movement (crying or taking a bm for example) may cause him to reflux or throw it up. A visit with your doc will help sort it out.
Temper tantrum. Some times children around this age do show different behaviour as a part of temper tantrum. If he is throwing up every time, i will rcomment r/o gerd, otherwise monitor. Do stay in touch with md.