Did you get injured without awareness? Other reasons for bruising are anti-coagulation medications such as aspirin, warfarin and low platelets. Regarding swelling, does this happen to your joint or soft tissue? If it happens to the joint, you have to consider other disorders such as arthritis; If it happens to the soft tissue, it might be concurrent infection. Therefore, if you have these symptoms frequently, you need to go to see a doctor. A hematologist would be the first choice.