Have Depression In Leg, Swelling, Not Painful, Knee Pain And Calf Tightness. What Could Be The Reason?

I am a 55+ woman. I am very active & play field hockey & squash. About 12 months ago I noticed a depression in my left leg,to the inside left of the shin bone. It was there most mornings when I got up but disappeared throughout the day. There is no pain associated with this. However, a couple of months ago I was playing hockey & at the end of the match I took my shin guards off & had a swelling that looked just as though i had been hit in the shins - I hadn t because I would have noticed something that hard! It formed a bruise over the next few days & went through the usual stages of black, purple, green & yellow - took more than 2 weeks to go completely. Now, whenever I play squash in particular both the depression & the hard lump return. They are not painful, only appear after exercise and so difficult to show a GP without taking a photo. I have very painful knees at the moment and tightness in left calf which is associated with meniscus tear rather than calf muscle damage. I don t know what this lump is - it is quite large when it comes up & very obvious - about 10mm high, 20mm across and 40mm long, whilst the depression seems to run along my shinbone starting midway down & running for about 60mm.