Can The Birth Control Implant Cause Pelvic Infection?

i'm 31 i had the implant fitted in feb 2009 an had not problems untill recently i started bleeding at the end of aug for 3 wks went to my doctor about it he said i had a pelvic infection give antibiotics the bleeding stopped 2 wks later after 3wks i have start bleedin again the last 2 wks sometimes light sometime heavy an very painfull is there a problem somewhere