Physiotherapy will probably be your best solution there.
Here are some possible reasons for your pain:
The muscles of your large toe may be in a protective spasm, resulting in mal adaptive firing and inability to relax. Additionally while injured there may have been some soft tissue changes in the plantar fascia which have changed the dynamics of the area in which the muscle moves for optimum function. The joint of the 1st metatarsal may be negatively impacted and not in optimal alignment. This would result in pain on the nerve supplying the 1st toe.
The physio for this should be soothing and relaxing, because it requires a lot of hands on treatment. A combination of massage, warm water relaxation, joint mobilisations, and finally muscle stretches should be done by a physiotherapist to help you get you pain free!
Cheers