Its the fluctuations of hormones that affect the gut which in turn affect the sinuses. The sinuses react to anything that shouldnt be in the esophagus by kicking in and dampening down. Very clever. You might not even be aware, or have any heartburn but the nothing should be in the esophagus. The spinchter muscle starts to relax caused by ageing, hormone fluctuations, and being over weight. I have bad sinuses everytime I over indulge, have my period, have a alcoholic drink, or get stressed ( when you produce more acid.) Its interesting that you said you feel bloated. These are just my observations, obviously.