I have an itchy feeling within the left side of my chest and pain but II don't exactly know where the pain, is occurring what should II do?

See your doctor. The symptoms you are describing could be a number of things but chest pain is one that needs further attention and evaluation by a doctor. An 'itchy feeling' with pain on only one side of the chest could be the initial symptoms of shingles(herpes zoster), and a red vesicular(pimple like)rash may or may not follow shortly. It is however impossible to be certain without going to see your doctor.
Could be shingles. Therwe are many possible causes for what you describe, but shingles (herpes zoster) is what your description reminds me of. If red spots and clusters of small blisters develop, i recommend seeing a doctor asap to get oral ant shingles medication to clear the rash faster and help prevent residual pain.