Started Out With Severe Right Thigh Weakness Then Injured My

Started out with severe right thigh weakness then injured my back lifting trash out of compactor. Thighs legs got weaker and pain settled in bright buttock and right lower back. 53 rear old female, have difficulty standing out of chair,takes concentration and leg feels really weak like I'm gonna lose balance or fall. When I trip hard to regain balance and not fall. Have h/o SLE