Shoulder sore from sleep on my hand badly, struggling to swing my hand when im swimming. ?

Sore shoulder: Simply sleeping on it shouldn't cause significant shoulder discomfort to persist that long. You may have developed a bursitis or tendonitis of the shoulder. Apply warm alternating with cold applications and take an anti-inflammatory medication like ibuprofen or naproxen for several days. If not improved see your MD or an orthopedic specialist for diagnosis and treatment.