What Causes Pain On Top Of My Left Foot?

hi im 23 yrs of age in the past i suffered with siatica it has been gone for quite some time now...for about a week i have been suffering with a pain on the top/side of my left foot it is hard to stretch and very painfull to put my weight on it i have done no injury what so ever but something is causeing this tremendous pain could you tell me what it may be i have been to the doctors and he said just take paracetamol which was no help at all i find it hard to rest it as i have three young children so im constantly on the go...thank you