Hi, I suffer from Neurofibromatosis and arthritis , back in January I had eleven nf tumours. Unfortunately one of the tumours that was removed from chest got infected, very inflamed with yellow puss coming fom it. I saw my doctor who took a swab and put me on Flucloxacillin 500mg four time a day. I followed instructions about food. My questions is I get very bad chest pain soon after taking this medication, the pain also goes in my back and last for a while. I am 54 years old and female, I don t smoke and I don t drink. Should I stop taking this medication? The chest pain is really bad.