K.H.
At Wal-Mart and BRU, they sell a swaddler with velcro. My little one is just now 5 months and I used to wrap just her arms for naps because she did the same thing. I saw one at Wal-Mart not very long ago that was lighter weight for summer.
If there is something wrong with yours, there is something wrong with mine, too and I don't think so! I think it is just a little guy not knowing what to do with these new-found skills of his!