27yo female, 7mm suspected bone island on anterior humeral head with shoulder/upper arm pain. Not on xrays 2 yrs ago. Likely followup tests/treatment?

Tested? a bone scan can be done to make sure it is a benign bone island and not something more worrisome. If it turns out to be a normal scan, then recheck of the X-ray in 6 - 12 months is the usual follow up to ensure the benign nature of the lesion has been correctly diagnosed. More tests to find out why your shoulder hurts may be indicated..... Like a shoulder MRI Arthrogram. See your orthopedist.