1. For reasons I'm not sure about, I tend to swell more if I walk outside vs. inside on a treadmill.
2. check posture. Perhaps stand more upright, shoulders back. Try to maintain that more. Check head position, no forward head.
3. If raising your arms doesn't result in a flare up...everyonce in awhile, raise your arms up to increase blood flow against the gravity of the arms being down. The swelling is common but not normal.
4. If you can, pack some ice in your fanny pack or back pack and try applying it as you notice the arms swelling, this may help to reduce or prevent the swelling.