What Causes Pain In Index Finger?

I am a 38 year old female and about 4 months ago I began to have pain in my right index finger. It is not swollen or discolored. The pain has gotten worse. It is now very sharp and it gets intense when I hold weights when working out, opening jars and even typing on the computer. The pain gets really bad some nights while I sleep and my hand is flat. What could it be?