28 year old. Physically fit male, no medical problems. Had a routine physical 3 1/2 weeks ago. Bloodwork everything fine except WBC 3.9 and low Vitamin D. Now I have 2 pea sized hard bumps on side to back of neck on left side. Worried? What can this be. They have been there for about almost 3 weeks.

From the location you mentioned they are probably lymph nodes, which are is our immune system's first line of defence for impending infections such as a minor cold. If you notice them by touching them, they may feel like a small hard pea size lump under the skin.

http://www.mayoclinic.com/health/swo...-nodes/DS00880