Thanks for your question on Healthcare Magic.
I can understand your concern.
Since your cardiac check up is normal,
costochondritis (inflammation of ribs and
cartilage) is more likely for your left sided
chest pain.
So follow these steps for better symptomatic relief in costochondritis.
1. Avoid heavyweight lifting and strenuous exercise.
2. Avoid movements causing pain.
3. Apply warm water pad on affected areas of chest.
4. Wear rib belt.
5. Take painkiller and anti inflammatory drugs like
ibuprofen or
acetaminophen.
6. Start calcium and vitamin d 3 supplements for faster recovery.
Don't worry, you will be alright with all these.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.