European Factors to Watch-Shares set to fall after strong rally

LONDON, Sept 17 (Reuters) - European stocks were set to fall on Monday, retreating from strong gains in the previous session on the back of a stimulus move by the U.S. Federal Reserve's, with shares seen as "overbought" and investors expected to take profits. The Euro STOXX 50 index's 14-day relative strength index (RSI) was at 69 - just below 70, which is considered 'overbought' and often triggers a sell-off. The index rose 2 percent on Friday and is up more than 26 percent since a low in J