My horse has some weird swelling going on on her right front.

I first noticed it on Mother's day, it's the inside of the leg, just above the fetlock, a little behind the cannon bone, at the end of the splint bone. Actually I think it is the end of the splint bones (the same bony structure is on her left leg, just that it's smaller on the left). It was a hard swelling, but the weird thing is that it was less pronounced depending on how she shifted her weight and it was almost not noticable anymore after riding.

She is not lame, nor does she show any sensitivity when you squeeze the leg.

A week later it was still there and I showed it to my trainer (she worked as a vet tech before). She said it's just the end of the splint bones and I shouldn't worry about it.

Now this week whenever I come out at night there is a small golf ball size soft swelling in that area, that also disappears with exercise, actually you can squeeze the swelling and it gets less .

She is still not lame, not sensitive and generally in good spirits.

But I do worry about anyway...am i just paranoid, should I just take my trainers advice and not worry about it?
Or call the vet and xray it? but what if he comes at a time when there's hardly any swelling and he will think I'm just halluzinating?

Plus a few years ago I wasted a lot of money and nerves on a lump on her jaw that I did call the vet for. He did a ton of tests, then diagnosed her with bone cancer and in the end it was nothing. She probably just bumped her head.

She did just get shoes on her front feet, so maybe she just kicked herself?