Chemo/expanders

hi there, just a quick one for you lovely ladies. I have just had my first AC treatment on Friday. I had the injection the following day to help with my white blood cells and they warned me that this could cause bone pain... which it has lol but my main concern is that it I feel as though my  expander ( which was done 2nd April and had began to settle) has really began to hurt and become uncomfortable again.... did anyone else experience this as a side effect to chemo?
thanks for reading xx