Is this normal?

I've noticed when I wake up in the middle of the night and/or first thing in the morning when I take my first deep breath I get a tickle like feeling in my lungs as though I have fluid in them. Sometimes I feel it at the bottom of my lungs sometimes in the middle but it always makes me cough and last night the feeling was there for over 5 minutes causing me to cough before the feeling went away. I don't remember having this with my other pregnancies so this is why I'm kind of concerned. Should I call my on call OB Doctor to see what they say? I'm 36 weeks.