Grunting, hiccupy baby-looking for advice.

My girl is 7 weeks and has been a grunter since she was born. She gets the hiccups almost everyday (sometimes 2xday), and often grunts and squirms for a good 20-30 min after nursing, sometimes more. Some days are better than others but it's pretty consistent. She seems uncomfortable but does not cry. I try burping often and sometimes that helps. Other times I can't get a burp out of her. She sleeps 4-6 hours at night but will only do 30-45 min stretches during the day for a total of 10-12 hours. I've tried swaddling and other calming measures to get her to sleep more to no avail. Sometimes she'll mouth like she's gagging when she's sleeping (but nothing comes out). I'm wondering if this is reflux and it keeps her from sleeping longer? She spits up often and has a projectile vomit every 2-3 days. My pediatrician said not to worry unless she vomits more than twice a day. She's gaining weight beautifully. I have her 2 month checkup next week and plan to bring it up again but I have a feeling the pediatrician will say the same thing as last visit. Any advice?