11 days post op (breast reduction) and I'm catching a cold.

Your BR may have weakened your immune system’s defenses and increased your chance of catching a cold. This is why your recovery period is so important. Make sure you get adequate rest, stay hydrated, consume 100 grams of protein per day in the healing phase for the first six weeks following surgery, and minimize strenuous activity.  If you think you need an antibiotic, check with your PS's office coordinator.Kenneth Hughes, MD, ABPS Board Certified Plastic SurgeonLos Angeles, CA

YES says best to inform your chosen operate surgeon of postop issues or be seen in a follow up appointment. Or you can see your Primary MD or see Urgent Care. 

Hello and thank you for your question.  I'm sorry to hear of your cold, however, as long as you take care of yourself, drink plenty of fluids, you should heal just fine.  I do suggest that you follow up directly with your surgeon to get his recommendation.  
Best,
Jon
Ver Halen, MD FACS
Harvard
educated plastic surgeon
Texas
“Top Doc”
RealSelf100
America’s
Top Plastic Surgeons, Consumer’s Research Council