What is this hard lump under my areola, 2 weeks post op gynecomastia surgery?

The hardness you feel under the nipple-areola areas is probably normal swelling or erly scar tissue. You should contact your surgeon's office even though it is out of town. Your surgeon will be the best one to guide you on this. 

The lump you are referring to under your infra areolar incision could be a seroma, a hematoma, swollen fat, fat necrosis, or even a stitch abscess.The answer to your question comes best from your personal plastic surgeon.  Text him or her a picture, ask the question, and gently but firmly request/demand an answer.Going out of town for surgery has its drawbacks, and this is one of them.  I am sure your plastic surgeon would be happy to see you, answer your questions, and give you the advice you need.

It is likely scar tissue or fluid.  Photos would not be helpful.  You really need to find a local surgeon who could take a look.  Perhaps, the PS who operated on you knows someone in the area.

Here's the thing... the lump could be many different things. It is literally impossible to diagnose it online. You need to be examined in person. This is the downside of having your surgery done elsewhere. Call your doctor and see if he can recommend someone in your area or visit the American Society of Plastic Surgeons website to find the board certified plastic surgeons near you and schedule an appointment. Best of luck.