radiation and abnormal pet scan

hope10

I had right right mastectomy in Dec. followed by  5 weeks of radiation. Finished march 4. All has been going pretty well, but i just had a pet scan the end of april. the scan showed abnormal and increased  uptake in the right upper long area?? Sometime i do have a sharp pain in that area.the doctors  are not sure if it is metz, infection, or effects of radation??? Any body have the same problem?  How soon did anyone have pet scan after radiation?

thanks for your help

hope