Watch the Slow Jimi - Solo online guitar lesson by Jeff Scheetz from Rock Solid
Changing this type of solo up can be challenging. Because just like how we like to change rhythms without totally messing up the tonality of the song, likewise when we are playing very melodic, we don't want to stray too far from our melody.
Use your ear and try things, but always allow yourself to be led back to the melody. Simple melodies should always win out - as guitar players we have to remind ourselves of that every once in a while anyways!