What Causes Hand Tremors Along With Temporary Memory Loss?

My hands shake on occasion usually when I am holding something. I I am scheduled for an M RI of the brain on March 5. My neurological symptoms include constant repetitive humming of numbers or letters with no significant pattern. I have also been having definite mood swings, short term memory loss, trouble finishing a thought, trouble multi-tasking,focusing on one thing, get easily distracted. The last five I have assumed they were symptoms of chemo brain from my chemo treatments for a carcinosarcoma of the uterus in 2011 with a recurrence in the right lung in 2014. What my question is could the tremors in my hand possibly be another symptom of a possible brain tumor.