I Had A Lumpectomy/ Lymph Node Removal 3 Months Ago

I had a lumpectomy/ lymph node removal 3 months ago was to start radiation a month later but ended up getting a staph infection doc never put me on antibiotics after surguery and all of this posponded my radiation treatment but i have been running al low grade fever and gave not been feeling well and getting burning and some pain at that same breast how do i know its not the cancer growing back is there a test