It is very fairly common to see a pullback near to neck line after formation of the pattern. It should generally be seen as a healthy thing as it gives better confirmation of neckline as resistance. In some case the pull back may happen few times. If this happens too many times then it may not be typical double top pattern. In case of pullback it is recommended to keep a stop loss of about 3% above neckline.
Volume in double Top has a lot of significance as it can help to confirm formation of the pattern. Volume during first top should generally be much higher than volume during second top formation and volume during midpoint formation should be much lower than volume during neckline break out Please avoid aggressive positioning when volume is not supporting the move. For aggressive traders a strict stop loss is recommended.