Improv

what do i need to know to improv on the guitar using the whole neck and not just a penatonic scales

Well if you want to improvise the pentatonic scale is excellent.
But the standard:
E 5----------8
B 5----------8
G 5------7----
D 5------7----
A 5------7----
E 5----------8
is fun for a while, but then you want more!

There are 5 different boxes that belong to the pentatonic scale,
we can call the example above Box 1.

Box 2:

----8-------10
----8-------10
7-------9-----
7-----------10
7-----------10
----8-------10

Box 3:

----10------12-----
----10-----------13
9-----------12-----
----10------12-----
----10------12-----
----10------12-----

Box 4:

12-------------15
-----13--------15
12--------14-----
12--------14-----
12-------------15
12-------------15

Box 5:

-----15------17
-----15------17
14-----------17
14-----------17
-----15------17
-----15------17

This is Am, but of course it can be transformed into any key.
Learn to play these like running water and you will find
improvising much more exciting.
I also like the phrygian scale and harmonic minor scales.
Those scales are a bit more metal, pentatonic is more blues/rock.