I'm a 28 year old male with a history of Hodgkins Lymphoma. In remission 5 years and well.

Recently I have had some mid/lower back pain when lying down at night and my stools have become loose and more frequent. Since January to June I have also lost some weight. 70kg to 66.5kg.

Been to the doctors and had;

 
blood tests (including; liver function) - All normal.

Chest X-ray - normal