Hi,
The commonest reasons I can think about are as follows:
*
Seasonal allergy causing nasal symptoms might have caused sneezing, the force of which can cause
costochondritis, muscle spasm of chest and thus pain on the left side of chest.
* Pleurisy and such conditions also cause
chest pain.
* Rarely any heart condition can cause such pain in a child of 7 years.
* Viral infection also can cause such symptoms
Hence,
consult a pediatrician to get the clinical examination, palpation of painful area to see whether there is any swelling, lump, tenderness. Any investigations like X-ray of chest to be done. Proper prescription based treatment should be done and a
second opinion of an Ophthalmologist can help to get a proper diagnosis and management for eye problems.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. T. Chandrakant, General Surgeo