You had muscle weakness in upper back at the same time you had more tight in upper Trapezius and you had more tight your pec muscles also so you will do stretch of pec muscles both side and apply ice constantly , you need now MFRs treatment it's one type of manual therapy then you do proper strengthening exercises for upper back muscles
Next Steps
You do daily some stretch and strengthening exercises for shoulder and neck it's more help for you
Health Tips
Any pain apply the ice its reduce your pain immediately