Many problems Lead to the battle of Badr:

The Prophet ﷺ‎    and his companions had migrated to Madinah. They had received a warm welcome there. They stayed there peacefully; preaching and inviting more people to Islam. But the Quraysh continued to remain very unfriendly towards the Muslims. They could not tolerate the rising fame of Allah,s Messenger ﷺ‎    . The rapid spread of Islam increased their anxiety. 
They, therefore, always looked for a chance to cause trouble and destroy the resettled Muslims of Madinah. 

Writer...... ABDUR RAHEEM AZMI