The 200, 50, 20, and 9 day MA's are stacked short over long. (Admittedly, that doesn't really portend that a very short pullback is unlikely, just that a significant one may not be on the way.) The OBV is high, yes, however, it was similarly high in the recent past and did not foretell a downturn (see November). I think the largest reason for skepticism is that this bull market has floated ever higher in the mid to top of its bolinger bands with short stubby candlesticks like we see here.
Tomorrow should be interesting as we'll get a test of the 20 day MA (on the other chart I'm looking at, today's low was very close.) My chart does show a MACDH sell signal and an RSI sell signal. I also see that implied volatility is relatively low but possibly hooking up (bearish).