I had poison oak for two weeks. It has now being replaced by a rash with small red bumps on my ribs, chest, back-itches, burns and a yeast infection?

Possible. looking at the rash in the picture without actually seeing the patient will suspected a viral lesion condyloma contagiosum. This can occur in patients with weakened immune system if you took Prednisone. It will spread by scratching it. It will usually resolve after a long time without treatment. Use anti itch meds may help. A visit to a Dermatologist may clarify diagnosis and help in management.
Too much prednisone? Were you on Prednisone / steroid pills for the poison oak? If so, that could result in the yeast infection. Otherwise, not sure about the small bumps.
What's the question. Sounds like a continuation of the poison oak which can last for weeks unless interrupted by treatment with steroids. If you have a yeast infection on top of this it might be a little concerning with regards to your immune status, but if it remains localized may just be due to the exposed areas of contact dermatitis. If your develop any other symptoms see your doctor.