Is this normal? tomatoes

I have a tomato bush that I have been given, it has loads of green tomatoes on it, I think it is a cherry type as the others she had had small tomatoes on them.
I lifted the leaves slightly tonight to check if I was watering enough/too much and the stem at the bottom has little brown nodules on it. I can take photos if I need to.
I just windered if this was normal or not? as it's my first time at growing anything.

Thank you. Our gardener who knows nothing about vegetable growing, just likes to prune bushes of which we have loads and he won't even cut grass lent me a book on growing veg but it didn't mention them. Thanks I can stop worrying now.