Brief Answer: can be costo-chondritis , a local problem. Detailed Answer: Hi. Gone through your past and present history. It is good to know that many of the tests you have mentioned are normal and rule out sinister problems. As the pain is in one spot under left breast, I can think of a specific problem called as costo-chondritis. In this condition you get a typical feeling and pain you described, It increases on local pressure , exposure to cold in anxiety states and flu and so on, so it continues. The mainstay of treatment is rest and pain-killers. Please discuss this when you are going to have next consultation with your Doctor. In some patients I recommend steroids in reducing doses over a three week period, doxycyclin, and an anti-inflammatory medicine, anxiolytic and so on successfully. As all these drugs are prescription drugs, they need to given ( prescribed ) by your Doctor. Please discuss this with your Doctor. Relaxing, avoiding the exposure to strain and stress does help a lot. Hope it helps. Dr Chandrakant

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