I dont' want to scare you but that happened to my husband 3 years ago and we found out he had a ruptured spleen - he had to have emergency surgery - died on the operating table - came back ....and then we found out after he had a terminal illness (NOT RELATED TO THE Ruptured Spleen)
sorry to be depressing but if it weren't for that spleen rupture we wouldn't have known WHY he couldn't breath - he was terrible about going to the doctor....
So - if this continues - you may want to go get checked out - it could be nothing but it could be something