Neck, shoulder, and back pain after exercise is usually due to muscle strain; rest, gentle stretching, and warm compresses can help recovery. You may take a pain reliever like Paracetamol or, if suitable, an anti-inflammatory like Ibuprofen for short-term relief, and apply a topical gel such as Diclofenac gel. Avoid heavy workouts for a few days and restart gradually; if pain is severe, persistent, or associated with numbness or weakness, consult a doctor.