Painful lump formation in right leg. Is?

Since a month , I am feeling as if my body has no strength , my legs ache a lot specially below the knee, few days back around 2nd of may when i woke up i had intense pain in my knee when i touched it i can feel some lump which was painful and there was swelling , due to that i wasn't able to fold my legs( i had medicine , i did hot compression ) few days later it vanished and there is no pain anymore, now i have same sort of lump at my inner thigh region and it's painful , and i can also feel a very small lump at my ankle when i press it it pains. I also have gastric issues , too much of gas formation in my whole body You can see the red spot in the photo , when i touch it i feel bump sort of inside my skin( it is stiff) and it aches. Please let me know what it is