5 year old always sick & lymph node issue..

[hball]

This actually goes back to August of 2008, when my then 4 year old daughter presented only a fever, high grade (near 106) for 12 consecutive days.  Multiple tests ran to no concluding diagnosis.  Her lymph node in her neck became enlarged at that time.  This same lymph node is now 2.9cm, and has never returned to normal size.  We've done ultrasounds, cbc w/diff., and sed. rate; but all come back normal.  Her doctor started antibiotics and wants to do a biopsy.  Let me say that she is sick at least every month since last August.  Usually presenting with only a fever and no other symptoms.  Should I have a second opinion by a pediatrician before I go ahead with a biopsy? Is a biopsy necessary if her bloodwork is fine? I don't want to put her through anything that might be unnecessary. During this ordeal she has become very difficult towards going to the doctor, as she's afraid everytime they are going to do a "needle". :( Please help!!