There are several theories that apply to working with dreams. The most famous techniques are from Sigmund Freud, Karl Jung, Isidor Fromm, Fritz Perls. In this case, I would rely on theory, Fromm. In it, dreams reflect our experiences, feelings that we do not address to someone, we do not place in contact, but we leave to ourselves, wrap it inside. I will say a terrible word - retroflexing. In life it looks like anger at yourself, self-accusation, self-shame, etc. The process of retroflection is reproduced in dreams. And if you are attentive to sleep, you can find out what kind of feelings you do not give to real contact. According to your dreams, this is anger. Sleep actualizes your anger at yourself. And if you return to an active life, then who are you really angry with and cannot tell him about it?
There may be other reasons, but perhaps you are uncomfortable sleeping, something presses, sticks, pricks. It happens to me. Try to flatten everything and sleep with or without comfortable clothing. Maybe you are somehow putting a blanket on, that something is crushing you or something is numb. Or you sleep on your arm. Maybe you have crumbs in your bed? :)