I am sorry to hear about your grieving and your debilitating symptoms. I strongly encourage you to see your primary care doctor
for further evaluation, as it is not possible to provide an accurate diagnosis with knowing your full medical history and performing an in-person evaluation.
Grief and other extreme emotional conditions can cause a multitude of symptoms, including diffuse body aches. Given that your symptoms seem to have developed during your period of grief, it is possible this is the cause.
A blockage in one of your heart's arteries (coronary artery disease) can lead to chest pain. This pain often radiates to your neck and arms. It is most common during periods of physical or emotional stress but can also occur at rest. Your question seems to suggest your symptoms last for many hours at a time, which is somewhat atypical for coronary artery disease. However, you will need to be evaluated by your physician to determine if this is the cause.
Additionally, aortic dissection, or a tear in your aorta, often causes tearing chest pain radiating to your back. It can also radiate to your neck and arms. This is a life threatening condition. Given how severe and debilitating your symptoms are, I strongly encourage you to see your primary care physician