Hi this thing came into my mind lastnight i was thinking about chords over scales and modes. let's say I have

C Am G and Dm and over these chords, if I would want to use a scale i'd be using C-major, ain't I correct?

But what about modes. if i use different modes, will I have to change my chords with them or are modes basicly based on same chords with different "scales?"

Sorry if you don't understand everything I meant to say
Any help is appreciated!
It is an interesting post, it shows you are thinking down all the right paths.

As you are well aware, your I - vi - V - ii is in C major.

The lead guitar over this entire progression with always sound nice using the C Major scale.

Your question seems to be, 'can i use different modes over the different chords?' and the answer may well be yes, but you then jump off your 'C Major ship of safety' into the 'non diatonic pool of sharks'.

If you wanted to highlight some colour over A minor in that progression, you would be within your rights to do so, but the 'colour' (ie non c major tones) would be out of the overall diatonic key.
This is not to say it can't happen.

With a fast moving progression, you will find it difficult, but if the progression was a slow few bars of each chord, you would be able to do almost whatever you like over each chord.

A think a good start point would be to experiment with scales that are only slightly altered from the overall key.

Lets continue with your C major progression, but over the Am chord, you will use A Harmonic minor. A harmonic minor uses a G# rather than a G. Play over the progression and over the Am chord, use this tone and see what you think of the results.

Other ideas would be to use D Aeolian over the Dm chord.... or think of your own.

hope that helped... maybe not
--^ it's a great start thanks dude, i was looking for answer something like that