What Causes Chest Pain While Breathing Along With Itching Under The Ribs?

2 weeks ago I had a cold, possibly the viral infection that circulated here. I recovered, but 4 days later developed a rash across my chest that appeared as red bumps, and was very sensitive. This went away after 1 week, but 2 days after disappearing, I suddenly started having severe pain in the left side of my chest when breathing. I went to see a doctor, and they diagnosed pleurisy and prescribed Ketorolac 10 mg. I ve been taking this for 5 days now, with no improvement. I have a constant deep itch under the ribs along with the pain, and there is now an area roughly the diameter of a baseball that feels numb, like a foot that has fallen asleep, under my lower left ribs. This evening, the rash reappeared, and I now have a golfball sized spot on my left side as well that has larger bumps. What could be causing this?