How come stock price increase doesn’t result in a volume increase as well?

The fact that the price went up means that there are a few people eager to acquire the stock, and some of the sellers are willing to part with them at a higher price. If we see high volume, it means there are lots of buyers wanting to get in, and lots of sellers are ready to exit at the resulting higher prices.

What is the best volume indicator?

The 6+ Best Volume Indicators in Day Trading

• VWAP.
• Volume-Weighted Moving Average (VWMA)
• Money Flow Index (MFI)
• Accumulation and distribution indicator.
• Klinger Oscillator.
• On Balance Volume (OBV)
• Other volume indicators.