Most people find that heat helps relax muscles better - although either can be used depending on how it makes it feel - local application of heat/ice is NOT going to do anything a a currative nature - more symptomatic treatment - whichever seems to help you best.
Laying flat - with your knees bent can help at times.
The weight gain could be from a number of things (Most people gain weight - myself included because we end up eating a little too much, and do less than we should) Other things that could cause this - fluid retention (are your ankles or abdomen swollen??)
There are two type of protein - Albumin and globulin. Depending on which is elevated would make a difference. Here is some information on protein levels.
http://www.labtestsonline.org/understanding/analytes/tp/test.html
Caution: If the globulin were the element that was elevated it COULD suggest a problem such as multiple myeloma which CAN cause back problems including compression fractures
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