LUMPY BREASTS

So I have stopped expressing. I have gradually reduced the amount of times I was expressing over 6 weeks and was only expressing once before I stopped completely In the last 2 days. Today will be my 3rd night. My boobs are very hard especially my right which I always produced more milk from. The left breast is ok. The right however has a massive lump I thought having a shower would get rid of if I gently massaged it. Instead my milk was just shooting out! I’m not in any pain however concerned as I don’t want to end up with mastitis!

Is this normal or any additional advice would be great! X