A quincunx aspect is when two planets are 150 degrees apart, (plus or minus 2, or 3 degrees). The sign each planet is in is very important because they have different qualities and elements and won't go too easily with each other's needs. Your Sun shows what you think is important and is the basic core of your chart that sort of holds everything together and it's how you identify with your sense of self. Any planet in aspect to your Sun will somehow influence how it's expressed in the sign it's in and as Pluto is in a sign with different qualities and element then in some way maybe Pluto interferes with your sense of self and finding your own sense of uniqueness, although Pluto in its sign is generational, it will be working in a different element to your Sun's element so eg if your Sun is in a water element, feelings and emotions are going to be important in how you express yourself whereas if Pluto's in a fire element, it's more to do with just getting on with it regardless, (sort of). which could lead to feelings of inner unease without really understanding why this happens sometimes. Find out which house your Sun is in and which house Pluto is in; there may be some sort of tension created between the two concerning intensity stemming from inner needs to get things done but for some reason doesn't usually work out too well perhaps.