In the past, taxpayers weren't required to pay Medicare tax on income generated from investments such as capital gains, dividends, and taxable interest. Since 2013, however, you could owe a 3.8% Medicare tax on some or all of your net investment income (as part of the Affordable Care Act).
Restless legs syndrome (RLS) is a neurological disorder characterized by uncomfortable leg sensations that can interfere with resting or falling asleep. Experts believe that low levels of iron in the brain may be responsible for RLS. An imbalance of dopamine is also believed to be involved.
A body that becomes overly stressed (stress-response hyperstimulated) can cause the nervous system to behave erratically, which can cause nerve impulses to fire erratically. Since nerve impulses control muscles, an erratically behaving nervous system can cause muscles to twitch. As long as the nervous system is even slightly overly stressed, it can cause erratic muscle twitching.