Early morning grunting?

For the last month my 6 week old has been nonstop grunting in her sleep from about 4 am until I get up with her. It’s not straining while pooping or passing gas. I’m almost certain it’s not reflux. She’s not congested. I’m pretty sure that it’s just something she does in her sleep. I read online that it’s normal. My question is, has anyone found a remedy for this? It keeps me awake for hours when I need to sleep. I’ve tried gripe water, swaddling, a paci....no luck. I’m ready to move her into her crib but I worry about SIDS.