How to get X and Y of any point in plot for excel 2010

To get values in between the plotted points, you need the estimated equation of the curve connecting the plotted points.  Once again, click on the line and then right-click and then pick:

Add Trendline...

You will need to experiment with the type of line to best match the curve.

Select Display equation on chart

once you have copied the equation into a cell, you can evaluate it for any input.

Excel 2010

Generate variable density grid pattern

in background with macro, then

mouse over points to read coordinates.

http://c3017412.r12.cf0.rackcdn.com/02_24_11a.xlsm

If you get *.zip, don't unzip, just rename *.xlsm

Once i click on the line, i can only be highlighted with the plotted points not the ones present in between the scatter plot.Any suggestions for 2010

Not sure if either of the below will work for you. Also, I haven't updated them in a while so I cannot indicate if they will or will not work with 2010:

Interactive Chart

http://www.tushar-mehta.com/excel/software/interactive_chart_display/index.html

and

Read X and Y value of any point on a chart

http://www.tushar-mehta.com/excel/tips/read_chart_value/index.html

The latter uses a feature that I believe Microsoft removed with 2007 and then added back through a free add-in.  If so, you may have to search for and install that add-in.