Hello A.!
L., here. Congratulations on the birth of your son!
I'm an IBCLC - International Board Certified Lactation Consultant.
There could be many reasons why your milk has not come in yet.
Frequent, effective stimulation of the breasts is essential. Baby needs to breastfeed at least 8 - 12 times each 24 hours. Most newborns breastfeed about 20 minutes per breast. Mothers hear swallowing sounds. If that's not happening, breastfeeding and then pumping 1 - 12 times a day with a hospital grade electric pump is the best way to ensure a plentiful supply while offering baby mother's own pumped milk as a "supplement".
Some medications given during labor delay milk coming in. Some medical conditions, such as cesarean birth, excessive blood loss at birth, thyroid disease and diabetes can cause a delay. Breast surgeries like augmentation or reduction can affect milk production.
The most likely reason, though, is that baby is not breastfeeding frequently enough and/or is not nursing effectively.
You might want to contact LaLeche League www.lalecheleague.org click on "fiding a group" to find a Leader in your area.
Or contact an IBCLC and get some assistance. www.ilca.org has listings - just click on "find a lactation consultant" and enter your zip code.
Please call LaLeche League or an IBCLC today. Hang in there - your milk should come in soon. All you need is a little assistance. You'll cherish this special time breastfeeding your son.
Happy mothering!
L.