Could be, but if it doesn't go away in a couple of days I would get a professional opinion.
Others have asked and received answers to this problem. One thing I've heard is that they should have supplied an antibiotic when the piercing was done, and of course, you should be using it. Other answers indicate that the posts should be left in the ear till you are completely healed. Also, you could be having a reaction to they type of metal from which the post is made.