Thanks for your question on Healthcare Magic.
I can understand your concern.
By your history and description, possibility of
musculoskeletal pain is more because your pain is associated with movements of
rib cage.
But since you are also having
numbness in left arm, we should first rule out cardiac cause for your symptoms.
So get done ecg and 2d echo first.
If all these are normal then no need to worry for heart diseases.
Avoid heavyweight lifting and strenuous exercise. Avoid movements causing pain. Avoid bad postures in sleep. Apply warm water pad on affected areas.
Take simple painkiller like
ibuprofen.
Don't worry, you will be alright with all these but first rule out heart diseases.
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.