Hi, I have gone through your question. I am a practicing anaesthesiologist and pain consultant.
According to the symptoms you have mentioned, it seems like
plantar fasciitis. Other possibilities could have been bony spur, deep bruise,
fracture. But as you have mentioned that MRI is normal, all these possibilities are unlikely.
Plantar fasciitis is inflammation of the band if tough tissues connecting toes and heel bones. Plantar fasciitis occurs when too much pressure on your feet damages the plantar fascia ligament, causing pain and
stiffness. As you have mentioned, pain is often worst when stepping onto the foot, particularly when getting up after being seated for some time.
I would like to suggest-
1) hot and cold fomentation
2) rest
3) stretching exercise- calf stretching, foot circle
4) pain killers like
paracetamol,
tramadol, ibuprofen
5) change your shoes- arch supporting or cushion soled