Re: What is difference between TSH and TSH Cascade?
The thyroid possibilities are large.
I can't comment much on the nodules and physical findings, although no one can say it's ever "normal" to have one lobe much larger or smaller than the other.
As for "TSH cascade"... It's a method of testing with a "cascade" effect. That is, if the first test performed - the TSH - is abnormal, it is only then followed up with FT4. If that's abnormal, it then is followed with more tests. The likelihood of finding a thyroid problem hinges on the TSH... which often is interpreted as normal when it actually isn't. Because TSH by itself is never conclusive if symptoms are present. I'm not a fan of this style of test. "TSH with reflex to FT4" is another such method.
The National Academy of Clinical Biochemistry most recently suggests that a sustained TSH above 2.5 probably isn't normal for anyone, and that a trial of supplemental hormone is called for in those cases if symptoms are present. The physical difficulties your gland has suggests it may be struggling to keep up with your hormone needs.