Is a soft tissue tumor and a soft tissue calcifaction the same thing?

Not exactly: A tumor can have calcification or not. You can get calcification in soft tissue without a tumor also, depends on the context.

Not the same: A tumor is a mass of tissue which is abnormal. Soft tissue tumors can begin in fat, muscle, blood vessels, tendons nerves & joint linings. A calcification occurs when calcium salts build up in body tissue. There are a number of causes of calcification. Sometimes a tumor may be calcified. Soft tissue tumors & calcifications are not the same thing.