In medieval times could a peasant get a job?

Yes, peasants could get jobs.

Serfs had jobs guaranteed to them, along with places to live. They worked farms, called manorial estates, and were not allowed to leave. While on the farm, the rent included a part of the crop, work, or money. There was time left over, if the serf wanted to do something else he could. Such work might be an advance over farming, and could include running a mill, weaving, making pottery, or working as a cook or servant in the manor itself.

If a serf left the land where he worked, and stayed off for a year, he was considered free. The up side of this was freedom, and the down side was loss of the guaranteed home and job on the farm. As a free person the peasant could get a job and work in the country or town.