Breast cysts

Hi I'm new to this forum so hoping you can advise me.few weeks ago I noticed my left breast felt different so went to G.P who sent me for a mammogram.The mammogram was clear but the D.R at the breast clinic also thought the left breast felt different so sent me for a scan.the scan showed a large cyst with a few small ones.The d.r said they were just harmless cysts and wants to see me again in 3 months.The last few days it feels like the cyst has gone bigger,whereas before the breast just felt "different" now it feels like a lump.is this normal with cysts? Should I wait for my appointment in breast clinic or go see my G.P?. It also feels a little swollen and is sore to touch.thanks in advance for advice x