Re: Sore arms 3 days after weight lifting?
It's quite normal to have muscle soreness if you're new to exercising. It usually stops after 2 or 3 weeks of regular exercise, unless you change your routine and start working different muscles.
You can work out again whilst the muscles are still sore, providing you've given enough rest between workouts (should leave 2 days between working the same muscle group really). Personally I would say you're working out the same muscles a bit too often if you're doing bicep/tricep every 2 days (so Monday/Wednesday/Friday/Sunday etc) - twice a week is the most you should really do on the same muscle.
Also I think your volume is a bit high - 5x20 reps = 100 reps total. Ideally you want to be doing more like 20 - 50 reps but with higher resistance. Is 2.3 kg the only weight you have available? Even if you just want to tone up, I'd recommend trying more like 4x12 at 4kg (or whatever weight makes this amount of reps possible, but difficult).
5 sets of 10 on triceps is ok though. What about your other muscles? Believe it or not, you'll tone up your arms a lot better if you also work chest/back/shoulders etc too, and it will give you a better overall look.