What causes sweater pilling?
Pilling is usually the result of friction yes, though how much it occurs - and whether it settles down quickly after a few wearings - depends on the material and construction. You won't avoid it because you will naturally move around during the day. Pick it off carefully by hand or with one of those defuzzer things if it's serious. If, more out of curiosity than practical remedy, you really want to pin what causes it, think about what you tend to do during the day. For example, if you're in a LHD drive car, would a seatbelt match the areas of pilling?
I am done with J. Crew sweaters for the same reason however. I personally feel you should not experience pilling of any significance in the first season of wear, even with heavy use. It is on this test that my first, and last, J. Crew sweater has failed. I get vastly better wear from RL.
Pilling is caused by the short and badly-integrated fibres of your garment becoming extracted and balling up on the outside of the fabric surface. Though usual wear will inevitably result in at least some pilling (as far as I've observed on my sweaters), it is exacerbated by sub-par fabric, friction, contact with abrasive surfaces and mistreatment when being cleaned.
You can pick a few off, but if they're noticeably numerous, it's often best to have a defuzzer at hand (as per Holdfast's advice). It should look somewhat like this.